A higher BB makes the bike stand on the rear wheel better, but makes it a bit more unstable on two wheels. It's good for static moves but you'll have to adapt your style slightly for rolling moves.
I HAVE to say the same thing. I got a set last week some time and my bike feels SOO much more comfortable, and I feel like my riding/style is improving.
I had an alloy bolt acting as a magura bleed screw. The head came off it, so the shaft(?) was stuck in the slave. And that was a bolt I hardly ever touched. I've never trust them again.
I'm guessing that because you run a QR it's the non-trials version. Look on Chainreaction or somewhere like that for what you need to convert it, as a trials axle wouldn't be up to the job I wouldn't have thought.
The 1st gen. ones, yeah. But the new ones seem up to the task. And as said, clean the shit out of it, bleed with water. No problems.
But still, get a magura!