Here is a link to a very recent thread on the subject: viewtopic.php?f=2&t=5359
I'd agree with WoW's points. On the bad sills, have you asked the remodeling company how much they would charge for that? Typically it is pretty reasonable (many companies don't even charge extra), so I don't think that it will drastically change the comparison. As long as the remodeling company is established and has a good reputation, that would be the way that I recommend going. Simonton is a solid window.