Ask him for more options or buy them yourself. Do a search on here and you will see what I mean. I am certain you can get a better window in the same price range.

For example what else would be a better window? What is wrong with the two I quoted, some details would be appreciated I am a complete novice.

As Millworkman said, do a search for those 2 brands. Some of the brands I always recommend looking at are Sunrise, Softlite, Okna, and Gorell. These manufacturers have a sterling reputation for consistent quality, excellent customer service and warranty service. In addition, they are all very low in air infiltration water penetration and all have very high design pressure ratings. I would ask your builder for a window credit and then contract with a window installation company who uses more sophisticated installtion methods than most builders do.

well said sky, could not have said it any better