Installed 7 Ply Gem/Great lakes windows in '92...2 more in 97. the older windows, while less steamlined - are of better quality and have held up better. another case of more money for less product. Both newer windows have had the external weatherstripping simply rot away. One gets very little sun - but, it would seem the material simply does not hold up. It is unsightly, to say the least - and keeps the windows from being tightly closed as designed to be. More importantly, one of the originals has a leak in the sealed glass. BEWARE of the claim "Lifetime Warranty" on sealed glass units - not true. It is a 10 year warranty which then becomes prorated from there on. 18 years later I must pay 70% of the present cost to replace the unit, $142.00, AND install it myself, or pay to have it done, into the vinyl sash. Just the purchase alone is nearly 50% the cost of the original window. Come on - the "heart" of these windows is the sealed, low E argon filled glass unit - if you are confident to only offer a 10 year full warranty - they cannot be that good. This is not a moving part that wears out from use - it is a manufacturing defect. Getting ready to do my 12 upstairs windows - this time I will use PELLA, also about 20% less in cost.