I first saw a System 2000 about 1988. As a jet engine fuel controls engineer, I was impressed with the design concept, which maximizes efficiency. I will give you the positives I know of, and then the minuses: Positives: The main idea of system 2000 is that it does not constantly cycle on and off to maintain the boiler at a constant temperature 24 hours/day, waiting for radiators or the domestic tank to call for heat. It only heats up when it needs to deliver heat, and then the circulator stays on for a few minutes extra to send the last bits of heat left into the rooms or domestic tank. It can do this because the boiler only holds about 2.5 gallons. Other boilers have varying boiler sizes, but they can be about 15 gallons. A 15 gallon boiler is probably too big to use the system 2000 concept, because 15 gallons is too much to heat and then cool completely each time there is a call for heat - so they are stuck with keeping the boiler hot 24/7 (unless you are heating a gymnasium). That is why the system 2000 stands out in how it operates. From what I can understand, the efficiency rating in use by the government does not factor in the heat lost when the boiler is idle. Most oil boilers, as far as I know from literature have efficiencies around 83-86%, which is driven by a good burner and lots of surface area between the boiler water and hot gases to transfer the heat. But the efficiency for most boilers is much lower when you account for the heat they lose when there is no zone demand. So most appear to be fairly close with respect to getting the heat out of the oil and into the water, but not as good as system 2000 when you include idling. Check the EK website - I can say I do not see anything wrong from a physics or thermodynamics/heat transfer point of view about their claims about efficiency. A condensing boiler can be as much as 90%+ efficient, but from what I have read getting this efficiency is not typical, real installations are more like upper 80's, but maybe they would work for you. I suspect they also have the heat-loss-when-off limitation, but maybe ask about this. My dad also had a system 2000 installed and it has been great. He burns a lot of wood and the sys-2000 is an excellent choice for his case, because when you are burning wood the oil burner is not being used for extended periods of time. If you want to see for yourself, stand next to a system 2000 when it is not providing heat - it will be cool. stand next to any other boiler when it is not sending heat to a zone - you will find various parts of it are warm - sending heat to the room and up the flue. I kept track of my oil use with this system and allowing that the previous year might have been a little different, the savings from my old clunker had to be in the range of 35 to 50%. I can vouch absolutely that most of the components are all standard - Honeywell high temp cutoff, low water shutoff, Honeywell ball type zone valves, check valves, oil filter, Taco circulators, temperature controls, all the plumbing, air bleeders, and of course, the burner itself is completely standard and can be cleaned and serviced by any oil guy. If you want to see for yourself download a picture of a sys-2000 from the website, go to Home depot and compare what you see in the picture to what you see on the shelf. (All the standard parts are on the outside - there isn't anything really inside the unit except for the insulation and boiler) I bought my oil from the guys who were the authorized dealers, but then I switched to my neighbors oil company - he was not a EK dealer - just a mom and pop outfit and they felt ok with it. There is a lot of small-time fraud in any technical industry today (cars, etc) from what I have seen and some oil men will take advantage of what they can to lock you in with high prices - so beware they will tell you all sorts of crap - the sys-2000 is ideal fodder in my opinion for some semi-scrupulous people to scare you into expensive contracts. The sys-2000 I had had only 3 parts that I know of that you will not see on other boilers: 1.the "system manager" (which on mine looked like it was a few LEDs, a few components like resistors, and a digital counting circuit - based on appearance - I don't have an electrical schematic or parts list for this board) 2.the flat plate heat exchanger for domestic hot water 3. the "boiler" itself, which is a type of heat exchanger - mild steel apparently. My setup did not have a digital temp sensor since it was older. The flat plate exchanger is attached with couplings meaning turn a wrench at 4 points and it comes off. Likewise system manager can be replaced quickly. I wasn't scared off by the high-tech appearance of the sys-2000 because it has so many ordinary parts that I have seen in home depot. My oil guy said he could service the sys-2000, and yours should be able to also, easily. If the 4 unique parts fail he needs to order them from EK. I liked the way it pipes in supply air from outside rather than the room and does not need the flapper on the stack - both heat wasters. Also, with less oil consumption the burner will run less often and should last longer. The system-2000 can give you high efficiency without a recuperator, which is a thing on the exhaust that lowers the exhaust temp. I am told these can leave a lot of condensation in the chimney. Now for the minuses! #1 Mild steel probably isn't as good as cast iron. You can get a cheap boiler like a Columbia boiler made of welded steel, and it probably won't last as long as cast iron from what I have been told - don't know this for a fact, but I have seen a couple cast iron boilers that are 50 years old and they haven't leaked. Don't know about welded steel, but my only experience was that the warranty is not as long it seems so that should tell you something maybe. However cast iron boilers are made in sections, and they have rope or silicone elastomeric (like rubber) seals, and cast or steel nipples connecting the sections, so that potentially could be an issue. #2 the system manager looks kinda hoaky - even though mine and my dad's did not fail, it doesn't look robust. I didn't see any type of surge protector on it, so maybe that is an issue. Also, in dirty/humid environments the circuit board solder joints on the parts looked like they are exposed, and who knows, maybe a little vibration and temperature cycling might make the odd one fail. This might benefit from a protective acrylic coating commonly used in the electronics industry, And maybe better power supply and filtering #3 It's believable the flat plate heat exchanger might clog up with the wrong water conditions. Mine and my dad's did not - but remember it changes out in a few minutes - four couplings. #4 (big one) My dad's friend had a sys-2000 go bad - apparently the boiler itself corroded and/or clogged up after about 8 years. Note the "boiler" has tight clearances because it looks like a jelly roll where the jelly is the water and the cake is the exhaust, which is good for lowering your heating bill but this maybe makes it a little more prone to this type of problem. EK has goofed up big time in my opinion by not making this part easily changeable. If they had, the whole system could be maintained indefinitely - there would be nothing that could go wrong without being able to replace it. My dad's friend apparently had water that was very inappropriate for a sys-2000 . #5 The system 2000 probably will cost a bit more to install if they are really trying to gouge you, but it shouldn't need to, but since the dealers handle a region, it's harder to get competing quotes - but maybe call the factory and gripe or look around. #6 Burnham had a competing model - I don't know if they have it still - best of both worlds maybe - cast iron mini-boiler with the same principle of operation as sys-2000, but when I went to buy one recently a heating guy said some Burnham customers were complaining of leaks - (I have this third party - so I have no proof of this). So maybe investigate this yourself. #7 sounds like the system manager is just different enough to fool some maintainers if it fails - try to get an oil guy who is smart enough to call the factory help line and/or use the internet, but if you are unlucky enough to have a bad manager, heat exchanger, or digital temp sensor problem, you will not be able to get these from Home depot, so it's a risk - however I don't know if all other boilers are completely absent of unique parts - maybe check into this. Summary: If you have a big enough house in a cold climate and your water is either not bad or conditioned if it is ( watch out for acid water with this or any welded boiler), and you have a good oil guy, this might save you so much money it will be worth changing the system manager, temp sensor, etc, once in a while hopefully not more than many years apart -check the warranty. And call the factory if you get a raw deal - they will likely come down on the abusers. And note the government efficiency rating does not appear to show the benefits of system 2000 over others. If the methods eventually change (based on the government or more consumers that pick up on the issue) I would expect improvements from many companies to try to compete with system-2000, so the consumer will benefit eventually from having more choices. lastly, everyone gets a little enthusiastic once in a while, so sometimes people have the facts a little wrong, that's why it helps to discuss things - but if we strive for the facts we will be better off - thanks