Very difficult to sum the guy up. He has endorsements from Zildjian using the super high end stuff just because of his videos. On a personal level, it seems that a lot of people can relate to him (just a kid with no money who wants to make music and has a modicum of talent).
Drumming wise he is perhaps better than me at certain things, but there are things I dislike.
1) His attitude towards certain songs. I cannot remember what video it was, but he said he covers songs where he thinks the beat is bad and wants to improve it. I don't think he understands why beats are 'simple' in some songs. I say simple because while playing 4/4 might be 'easy' if the feel isn't there it can sound completely wrong.
2) He seems to just cover what people want him to rather than spending time improving his playing. Now he's got his endorsements perhaps he needs to work a little more on progressing (unless thats part of his contract then he will be stuck in a rut for a long time).
3) Songs like 'The Pretender' do not need to be improvised, but he jams over the top of them with stuff that just does not make sense. All he has done is bastardise what is a very good drum track by Taylor Hawkins. And people still dig this stuff.
It all amounts to a point scoring exercise. I'm very glad that he got declined for America's Got Talent, his playing is not awe inspiring. Fair play to him for having a go of course...
I only look at drum covers to get a reliable guide for certain tracks I want to learn, like Superstition, I feel good etc. The only purpose Casey serves me, is to remind me that not all popular drummers are superhuman. If one things exposes his playing over anything else, it's his drum solos on his big kit. Too much trickery not enough competence for someone who gives it the beans about how great they are.
I'm envious of his endorsements, he is a lucky son of a gun. That's all that I'm envious of though...