1 – Actively angered me. Not just a negative experience, but one that I considered actually hurtful and a negative influence on the world.
2 – Terrible. Nothing good about it.
3 – Bad. Maybe it has one or two spots of light, but the negative heavily outweighs the positive.
4 – Mediocre. Nothing I'd recommend, and maybe just mundane, but it's either not actively inept or it has some good things mixed with bad things.
5 – Has potential. It doesn't achieve the point where I'd recommend it, but there are definitely interesting things about it. Normally pretty uneven, but clearly made by someone who has ideas.
6 – Solid. This show is a respectable version of what it is trying to do.
7 – Good. This show is noteworthy, and probably has some inspired ideas. I'd recommend it.
8 – Excellent. This show is a stellar example of its genre, and most people who share my ideas about art would find it compelling.
9 – Exemplary. This show is either a flawless execution of its genre, or it does something utterly unique and inspiring.
10 – Transcendent. Why evaluate shows like this according to some chart of aesthetics?
I actually consider my 10 a pretty broad category at this point - it's just the point where overt flaws no longer become greatly relevant when discussing a show, since the show is good enough that I can just say "this is a great work" with no real caveats. At that point, a hierarchy seems like a silly thing to apply to shows - if a show has noble goals and executes them in a pretty much flawless way, why would it matter if it is slightly more flawless or slightly more ambitious than another such show? All of them should be watched.