Dove windows quality, reliability?

[icooper]

I live in Baltimore City Maryland in a 1928 vintage cottage. I have just gotten a quote for 17 vinyl replacement windows. The contractor recommends 13 double hung Dove 6000 series for the living area and 4 Dove 2000 Plus slides for the basement windows. The U factor is 0.29 and the SHGC is 0.27. Does any one have any recommendations about these windows? Any guidance would be greatly appreciated.