The population and stability of the servers is pretty amazing so far. And the devs and GMs respond fast and fix the bugs pretty quickly. However, there's still tons of bugs out there left to fix.
I am however disappointed in the amount of bugs, but recently I saw on moO_UK's stream that all the ZF stair event + gate bugs from the test that me and a lot of other people reported: All those bugs are still present in the exact same state and way as they were bugged on the tests. - This is not good. Zul'Farrak stair event still broken. Doors still don't open.
There's lots of bugs.. But if the devs keep up the speed they've been fixing stuff at so far, it could end up very well in the end.
Let's just hope that endgame content isn't so bugged...