dh wrote:Look on ebay, vinteck sells them cheaper
Pretty sure that was the vendor on eBay that I got mine from last year. Ended up buying them from him over the phone bec. I had a lot of questions I wanted to ask before hitting the "submit" button on eBay. The downside to that was the fact that he tacked on taxes, whereas they would not have been charged on eBay.
All in all, they worked great and I was very happy with them. Took me a bit of time (several practice holes on scrap wood) to make sure I got it right. I think the cost was in the mid 400's -- sizeable, but not $600. Prices may have gone up now though.
For me, I liked the fact that I didn't have to buy all the individual parts (windows, hinges, handles, locks, etc.) and then manufacture it, all while being water-tight.