Personally, it's too much risk for me to see a provider without solid reviews.

Of course that's partly due to the money involved. But also, irresponsible or inexperienced providers can introduce health risks, legal risks, and even potentially social risks (if the relationship doesn't stay professional).

While not a perfect solution, reviews help build the trust level, and go a long way toward establishing the comfort I need to have in order to take those risks.

That said, if someone has hundreds of good reviews, that doesn't do much more for me than having 5 or so good reviews, from reputable reviewers.  Also, there are probably other ways to build that trust, like meeting in person at M+Gs, referrals from friends, that kind of thing. So I suppose reviews aren't absolutely necessary, but so far, they're the main thing I use to make a decision on whether to see a provider.