I did not mean to imply that more expensive is better, it not always is. It's a business transaction so you need to look for professionalism, and not just "sales professional". You want a contract that includes all the specs you want. That way, if they don't deliver, you will have recourse.

I am not familiar with roof hangers, we live in the south and my daughters roof pitch is only about a 6/12. I would ask about the size of the screws used and the gauge of the metal used in the gutter. You might not need the 6" gutter, a 5" will probably do unless you get a lot of rainfall, but the gauge will make a big difference in durability. BTW, the smaller the number, the thicker the metal. A 14 or 16 gauge would be preferable to an 18 or 22 gauge. I don't know what gauges are available in your area.