Exactly.
If you are content with a product, you are busy enjoying it. People upset at something find any outlet they can to vent (welcome to the room, internet).
I found my current employer on there, we rate well
I agree, if you read the product reviews on builders you would never build with anyone.
I find that people who write reviews are invariably the unhappy ones. People that have an average normal experience post nothing and even people that have a fantastic service tend to be slack about reviewing.
Whilst I agree with all three of you above, the old saying of no news is good news is applicable. Fact is that whilst 99% people who have mediocre or fantastic experiences with builders are less likely to post, that still does not discredit the many negative reviews. The number of negative reviews has got to be alarm bells, taking on board people's experiences gives you a good idea of what to watch out for, even if you do decide to go with the company.