My folks have a new build house (built circa 2003), not sure if it's Barrett or not (think not) but I'll highlight what I can. It's a terraced three floor town house btw.
- Insulation is very good, only the ground floor is ever cold when the heating isn't on. Dining room/kitchen has a ceiling fan because it's unbearably hot eating in there when the oven and hob have been on.
- Some of the build quality is terrible - particularly the plumbing, a few years after they moved in the shower base started sagging, and a dead rat was behind the wall in the downstairs toilet.
- Parking; all the houses down their street have a garage and a drive in front of it. No-one uses their garage, they're just too small for modern cars, so everyone parks their second car on their front gardens (which are gravel). I'm afraid it's one of those stupid developments where the council will only give planning permission if they make street parking difficult, which just means that people park on the pavement which looks a bit scruffy. There are some dedicated spaces for visitors though so not usually a problem when I visit (though one guy claims they belong to him

)
- Living room is an odd shape making it hard to find a layout where everyone can see the TV.
- Never had a problem with soundproofing as far as I know. Sure if the neighbours are doing DIY you can hear the drills, hammers etc. I'd say the soundproofing was a lot better than in my 1970's era terraced house.
Overall, it wouldn't be my cup of tea but it suits my parent's needs quite nicely - they only live there approx 6 months of the year anyway.