Know nothing about rain gutters.
What questions should I ask ?
Are there different "quality levels" ? e.g., Aluminum thickness, etc.
Is there a consensous as to the best brand(s) ?
Also, is there a best method of fastening the gutters with a particular
type of hardware that I should be requesting ?
Just be sure to get continuous or seamless gutters, as you don't want
to end up climbing a ladder often to apply sealant to all the joints.
As to fastening the gutter to the fascia, I'd recommend that the more
fasteners used, the less you'll have to worry about them. I like the
hidden type that attach to the inside of the gutter lip, and are
fastened with a screw into the fascia.