The number system for the reviews doesn't always accurately reflect whether something is good or bad. Depending on the situation not training anywhere official isn't a problem, and other times you need to at least have a gym if not dedicated space. Having a seperate rating system style by style or category by category would be better. The things that are crucial or at least very important differ depending on what's being trained.

If the place focuses on grappling, having mirrors is bad and pads around the walls is good. If the place focuses on striking, having mirrors is a good thing. Same thing with showers - a grappling place really should have showers because of the risk of ring worm - it's good to have them in any situation, but lack of showers isn't as big of a deal. Space is really dependant on what you're doing and how many people are training. If you have 3-5 people training, you really don't need to have much space. If you have 40, then 10,000 square feet would be nice. Having space is also more important with grappling, since any good grappling school does takedowns, you need a lot of space to be able to train takedowns properly. Even if you only have 2 people, there's a minimum space to work with - at least 40 feet in one direction so you don't have to worry about running into walls on a double. Good striking also has a minimum but can be confined to a smaller space with the same number of people.

Even though there's degrees of rating for the striking, it's too general. A sport BJJ place can get away with only starting from the knees, even though it's not great to ignore standup. An MMA place can't get away with not having any standup grappling and takedowns.

So, for each style that you know well, what are the important questions to ask?

Some for MMA.

Does the school train striking that's adapted to MMA or is it standard Muay Thai/Kickboxing/Karate/etc.? (Or none at all, in which case it's not MMA)

Does the school train takedowns that are adapted to MMA (both striking and submissions), or is it standard wrestling? (Or none at all, ")

Does the school train ground fighting that's adapted to MMA (incliding striking from all positions) or is it straight submission wrestling? (Or none... etc.)

Does the school have a range of training from highly technical focus to intense sparring or does it sit heavily on one side of the range? (Ie, too much technical training, not enough sparring, or too much intense sparring with no work on technique)

Is the training alive, are combinations and techniques done without resistance or is there always some form of resistance?

Is there a clear system that's explained to everyone or is there a collection of techniques that don't tie in together very well?

Are the conditioning workouts sport specific, or are they more generic?

There's definitely more but that's a good start.