How many reviews do you think are enough to feel comfortable? 6, 7, 8? If there are only 8 or so but are reviewed by people with a lot of other reviews does that make it more comfortable?
The exact number of reviews could vary case by case. When a local indy has been reviewed by known and established reviewers; it adds much credibility early on. However, many reviews submitted by first time reviewer(s) could just be less believable.
We had a situation in our city where a group of girls had pages of reviews, mostly from one-timers. They were ultimately pulled, because they were posted in violation of TER rules. I've met guys that saw some of the girls, and were pleased with the experience, but they wanted a volume of reviews, so they made them up.
Point is, the value is in reviews by people you trust. Look for familiar names; look for other reviews by those people (see if they like what you do), and ask them specific questions.
In the overall picture, reviews help to establish that the lady has been around for a while and is stable. A lady that has been around for a while and been positively reviewed by familiar names is what I look for.
What matters more to me is the reputation and history of the reviewers. There are a few reviewers in the DC area, for example, whose opinions I trust. If I saw a provider profile with only one review, but the review was by one of these trusted reviewers, I'd take the chance.
Of course, multiple reviews by people with extensive review histories just sort of solidifies the assurance that you're dealing with a quality provider.
Find a few reviewers who seem to have their stuff together and write well-thought-out reviews. See what they have to say on the local board.
But yes, in the absence of a trusted set of reviewers, more reviews by experienced reviewers is a good sign.
Enjoy,
-PV
an answer. The more experience hobbyest might go with 2 or 3 reviews if he can recognize the reviewers as solid reputable sources. Stay away from 1 time reviewers with no history.