I've only done a very tiny amount in it, basically I've spent some time at the target dummies as BM and as MM.
Re-doing the 4,800 hunter keybinds from memory was a pain.
I feel like my guesses at how to play BM from the previous blog post seem like they were pretty much correct. It's really, really rough going back to default UI with a 6-second cooldown signature ability, though. I keep having to flick my eyes back and forth between the middle-bottom of my screen to look at action bars and the top-left of my screen to look at focus. At some point they really, really, really should bake some improvements into the default UI. I know they've at least provided semi-functional raidframes for healers, but looking in totally different quadrants of your screen for cooldowns and resources is honestly terrible.
MM also seems to be much the same as it was. Keep Chimera Shot on cooldown, keep whatever the renamed ISS buff is going, dump focus with Aimed Shot.
Both specs were - I'm sure - easier to play with my T13 2pc bonus.
I'm running around on my bear trying to locate the entrances to dungeons at the moment. It's... it's not straightforward. I'm hoping that once I do locate them, I'll be able to fraps some video in various specs. Of course, there's also no recount or anything? So I have no way of comparing damage really. Still, it'll be nice to get a feel for how things go.
I'll keep y'all posted!