A couple of people on a forum complain about issues with their Harron home and all of a sudden "This really does appear to be one of Britain's worst house builders!"
I'm in the process of buying a Harron home (it's currently about 6 feet tall) and have done a hell of a lot of research. Try searching for reviews on Harron homes and you'll hardly find anything. In fact on the whole of the internet I think I've found two threads on the subject. Whilst they are only a small builder, if they were as bad as you make out, there would be a hell of a lot more people complaining.
On the other hand, try searching for reviews on Barratt, Taylor Wimpey, Persimmon, Ben Bailey etc. etc. People have created websites complaining about them.
All these builders employ the same trades and unfortunately some are either careless or just not very good. You'll never find a builder with 100% customer satisfaction. The trick is to take a considered view.
I have spoken to several couples who have bought Harron homes on my development and all are very happy. Yes there has been the usual snagging problems but nothing critical.
Luckily I'm level headed but some folk will read your negative, "mountain-out-of-a-molehill judgements" and be put off.