They're not that bad to bleed, I did it fine with a DIY bleed kit. Had loads of problems with them, sent them to the distributer to get fixed. They didn't fix the problem and their "bleed" was shockingly bad so had to bleed again myself.
I've got 2 pairs on 2 bikes. They're cheap and they slow you down and I like the lever feel. That's why I've still got them.
More powerful than nines? I wouldn't say so. I've been using nines for ages and I don't think the difference between the 2 is hugely noticeable.
As for mounts, aye use the old ones.
I got 1st pair off CRC for £70 odd for the pair and 2nd pair from Merlin £70 odd again with no rotors. For the money why not.