Lowe's did a good job on mine. Double hung with full screens, that was close to 15 years ago, I'm still happy with them. I don't have the contractor's name with me, but I will post it when I can.
But then again, I have Mad CKow so who knows if the windows are real.
Shop around. I called everyone (including Lowes, Home Depot and other big name stores) in a 4 state area (KS, OK, AR, MO) and the best deal that I found was a lumberyard in Siloam Spring, Arkansas. In fact, they beat everyone's price by at least half and they were custom sizes!
I just had Lowes install two three replacement windows and they ha to move one window in 1/2". To do this, they had to remove a marble sill and cut 1/2" off to accommodate for the thicker window. They cut the marble sill in the wrong place before they realized their error and reinstalled the sill and covered up their mistake with 4" of caulk which is evident and didn't bother to tell us. Then there is the glass they left on the carpet which isn't too good and that's why I'm looking for a "good" window replacement company. I'm not being picky but cutting the window sill and not telling us was dishonest.
And I agree with TwoForFlinching as to installing them myself, the job will be done right that way but the problem is, I am in need of a total shoulder replacement and hurt.