Ply Gem Grand View 4000 dbl hung - few questions

[windows4ted]

Hi all,

First off, thanks for this resource. I can see lots that there's lots of knowledgeable folks here who offer up helpful advice.

I am having some Malta double hung windows replaced--right now probably three but before it's all said and done (couple years?) probably ~15. The house is about 14 years old and I've had condensation issues leading to wood rot (presumably my fault) and several seals going out on the Maltas. Since I am not the original owner and I live in a humid environment (southern tier NYS), I'm leaning toward a vinyl replacement window. I love the wood, but I think some degree of condensation is here to stay. My contractor's wholesaler has quoted this initial job based on Ply Gem's Grand View 4000 windows. I went and looked at the window the other day, but I could use input from anyone knowledgeable about these windows. I would appreciate any general feedback about that line, specifically the double hung windows. How do the latches, seals, and weatherstripping hold up on these units?

I have had no luck accessing the NFRC website, despite trying from both a Mac and a PC (Firefox and IE 6.something). Great Lakes has documentation stating that the NFRC ratings are as follows (for the HP2 glass):

Total Unit U-factor = 0.30
SGHC = 0.24 - 0.27 (depending on the grid inserts)
VT = 0.42 - 0.47 (also depends on grids (?) )
CR = 53

Great Lakes provides their own ratings as well:

U-factor (center of glass) = 0.25
R-value (center of glass) = 4.0
R-value (total unit) = 3.3

I haven't found any rating for air leakage rates for the unit as a whole, and I am curious about those. From reading on other sites, I have a couple additional questions:

The SGHC index seems very low compared to what I've read about. Is it correct to interpret the 0.24 - 0.27 as the percentage of available heat that will be coming in these windows? That value seems a little on the cool side for winter, even though I think it will be a good thing in the summer.

I don't know how to interpret the VT. I've read that anything less than 0.50 will begin to seem dark. Is 0.42 - 0.47 going to be noticeably darker? For all I know, they might be right in line with what I've got now in the Maltas.

What's the general consensus on the value of the Grand View 4000 line for this application? Though I don't necessarily want to spend top dollar, I do want good value and am willing to pay more now than to have an inferior product and have to replace it prematurely. I do understand much will hinge on my contractor, but I think I've got a good one based on local (non-invested) recommendations.

Thanks in advance for your input.