Like any deal buying a home can go anyway, I bought a new home from another builder, Linden Homes, who have a good reputation locally but I still had a snag list jobs that needed doing so I'll guess you'll get this not matter who your builder, I think the builders leave a lot of the QA to the house buyer as you'll probably pick up less than a professional (who they don't have to pay) and they'd only have to fix it any.
Social housing is one of those things these days and there's different levels, we've got association (why do they sit out in their front gardens to drink and smoke), affordable homes (people trying to do their best) and standard home owners, the way the estate is built you drive through the non standard homes round a corner to the home owners area so it kind of works, it's also a cul de sac so that keeps the rif raf out. Don't assume mixed housing is automatically a bad thing.
As far as price goes I'd try and get at least 10% off and as many freebies as possible. I paid full price for the house which is quite embarrassing when I look on the website and compare my purchase to that of the neighbours, however I got load of things included, carpets, grass, bigger fence, built in wardrobes, free legal and a £500 voucher for registering on their website. I also part exchanged my old house and got well over the market value for my old house then had no sellers fees to pay, or any of the hassles selling, both of which combined would have been worth around £20k or just under 10 of the house price, they will be making at least 30% profit so get yourself a slice.
Then you've got a home that should work as expected for at least the length of your posting, will be cheap to heat, will have plenty of plugs and other things that modern living needs and still be in reasonable nick when you come to sell. There are some costs but then again what you spend getting the house how you want it would have been spent maintaining an older house anyway.
Good luck and don't get suckered in by the sales agent, he's not your friend you are his pay check.