Most of the SPs I know, myself included obviously, read their reviews, as well as others' reviews. I also lurked on Terb for a couple months before entering in the business, learning about the typical services and run-down of an appointment, and getting a feel of the differents agencies in the biz. I've certainly picked a trick or two from reading reviews, but contrary to what the OP's question implies, not from my own reviews: for instance, I would read in another SP's review about a little detail that made the client feel great (enough to mention it in the review) and make a mental note to do the same in the proper circumstances.
So, yes, some of us do read reviews as a form of "constructive feedback". But for me, it's more about the little details than the intimate part of the encounter.