I've played it a few times, my overall experience is that it could be amazing, but doesn't tend to be.
So maybe it's just the servers i've played on but the general gist seems to be:
They have races and derbys you can join, 2-3 people join and often quit early.
There isn't enough people on the servers one or two servers with 100 people, others with 9.
Theres NO npcs?!? that means no cars anywhere apart from parked in certain areas
Everyone seems to want to kill you so its one big free for all, without exactly good aiming.
You can /tp about on most servers, good fun i like that.
Basically it comes down to a free for all where people spawn airships, don't die easily maybe because of lag but they flip about a bit.
Its like GTA but without cars everywhere and less precise shooting. (although ive never played a gta multiplayer game, i'd imagine it does it better).
Fun and worth a try, but you won't sink hundreds of hours into it is my general opinion.
P.S i've just been pugging it, if i had friends dedicated to doing stupid stuff on it, it could well be good fun.