Bottom line: School Spirit was worth the watch for me. It's a stock slasher film that is generally forgettable, but isn't a bad watch, and that was what I expected. If that's what you're after, you'll probably enjoy it too.
Gore level is pretty low for anyone concerned with that.
It doesn't feel like a B-horror, it's just a standard "breakfast club"-style slasher flick. The pacing, production values, and lighting are all decent for the most part.
At the end of the day there isn't a ton of stuff to complain about, but there also isn't anything memorable. There are a couple fun kills, but most of them are boring and done off screen. The cast is alright, but the majority of the script isn't very good so the dialogue is lacking. The "twists" are predictable, but fun.
Some of the logic and the murky timeline don't stack up well, but not enough to really bug me for the kind of movie this is and the expectations I had going in. I'm not going out of my way to recommend it for people, but if you like slashers then this one is good enough!