I would be cautious of putting too much weight on those product...

I would be cautious of putting too much weight on those product ratings. Firstly there is selection bias, in that only people with a grievance or incentive post on such sites, so even if 90% are happy then it is the remaining 10% that will post reviews. Secondly, many companies try to game the review process by offering incentives to customers to post reviews (which will positively bias), or even just post fake reviews themselves. Looking through some of the higher rated builders I get the feeling that this is the case, although I don't know for certain.