What compels a guy to see a provider who's clearly YMMV? Do guys take it as a challenge to prove they will be nice to you, or is it because they are insanely hot and you just can't resist the urge to see her?  
I see reviews for a lot of providers who are amazingly hot (GG or ts) but they're reviews in a lot of cases are all over the place. Yet they keep getting reviews... I mean... People keep seeing them for a reason.  

And being on the higher receiving end of YMMV

some things I might not care about at all.

When I write a review and use ymmv I know that we did not connect well enough, and maybe the next guy will have better luck connecting with her. So when I see it use n her review I figure just maybe we could connect better and I can have a good time with her. Unless it states about kissing, or daty, then I move on. That is what I am looking for mostly.

....at least are somewhat predictable when it comes to timeliness, hygiene, non-ROB, etc.
My service needs are very unique and specific so most of her review xxx details are not of much interest to me anyway.

I'll chance it on the YMMV...Just to be all over the her, it's like what the heck..so I know what I'm getting into, anything above that is gravy.

When I see too many inconsistencies and ratings all over the board for a provider, it throws up a red flag and I would think twice before seeing her.  Although, that's just me.

My interpretation was that I was getting something(or thought I was) that most others would never receive. I guess that would really be MMMV, I always thought they were talking to me.

Once that feeling of sexuality overwhelms you, it inhibits your decision making process. In this instance it's a case of who's available, rather than who has the best reviews. In real life average to poor reviews can help you improve, or drive you out of a business. Not so here. Thank God I'm above all that, and patiently await her availability.

There are some clients that feel compelled to see every provider at an agency regardless of her reviews. Also, an agency that has formed it's own little community can be, if not impervious to TER reviews, at least able to market those providers as 'wild cards' to be seen.  Sort of a lottery effect that gives the girl plenty of buzz. Agency owners may befriend some of the whales, so when a popular one gets one of those 5 performance scores, she can sometimes setup a damage control appointment and review. Having been in that situation before, I recall it being a little like raising your FICO score. Lol

I used to be good friends with the owner of a fine South Florida agency. She would ask me to "audition" ladies from time to time. Free playtime and great performances!

During damage control calls, it's beneficial to warn the provider that she is seeing a reviewer, but an audition call is sometimes more of a secret shopper thing. The provider is hired, but is being 'checked out'. However, it's not too hard to spot a "Bestie":

I normally won't because i look for specific things and i want to be sure i get them so if it says ymmv on those things it's not worth the risk of being disappointed and feeling like I wasted my money.

a ploy. I mean if a provider says Greek is YMMV
and then asks the client if he wants to go "To the Islands",
when she really offers Greek anyway to all clients,
It makes the guy feel "Special"
and feeling special is what the hobby is about ... isn't it?

If service is consistantly bad in reviews I wouldn't see her. Your OP talked about YMMV. YMMV does not mean consistantly bad. It means that service varies.

This way he is not only a loyal customer, but becomes one of their biggest cheerleaders as he feels he is part of a team. I am sure it can be a bit aggravating to some of the girls, but it's great for the business of the agency, until and unless the owner and the client have a falling out and then the client takes on the persona of a "woman scorned"