The Plygem Great Lakes 4000 is a decent window. Make sure you upgrade to the Maxuus glass package like Hartford said.
4000 Double Hung with Maxuus (Double Low E Argon)
U-factor = .30
SHGC = .27
without Maxuss Glass
U-factor = .31
SHGC = .26
The tax credits have been converted to 30% of the cost of the windows up to $1500. A $5000 purchase will get you the maximum $1500 credit. (The previous $200 cap on windows has been removed.
The new standards are that the windows have to have a minimum NFRC U-Factor of .30 and a minimum NFRC Solar Heat Gain Coefficient of .30
Vinyl is a durable product, it has stood the test of time. (Over twenty years for most the large manufacturers)
The expansion on vinyl is so minimal, you will most likely never, never, I mean, NEVER see a problem because of this. Unless you live in Arizona and put the windows facing south west, no cover and paint the windows bronze. You might see the breakdown of the vinyl integrity. You have to get the window to 160 for the PVC to become pliable.
I've seen vinyl windows I put in 25 years ago (that have been washed regularly) that look and operate almost like the day I installed them. Not all vinyl windows will though.
The installation methods, the size of the window, the type of the window, the counterbalances used in the window (if double hung) and the success of the spacer system all have their share to do with the longevity of the window.
Vinyl windows have a better performance. Better U-factors,Better DP Ratings,Better Warranty then most wood windows. You can check check for yourself at the NFRC website. Here is a link
http://cpd.nfrc.org/search/cpd/cpd_search_default.aspx?type=W
Also replacement windows
do not come with a nailing fin. Nailing fins are usually for new construction windows.
Make sure you check references of the company and go see a few jobs done by the installers.
Good Luck with your purchase