I've the new(ish) XT's.
Power is good, but very imediate if you really squeeze they're still no more powerfull than anything else (not suprising they're still limited by the same laws of physics). Their advantage is they don't require much force to generate 90% it, thus less fatigue on long decents with hard braking over bumps.
Ice tech might work, I've not done back to back runs with the standard 2 part rotors, but I've not overheated them despite being a 15stone [s]powerhouse[/s][i] lard arse[/i].
There is a difference between SLX and XT, but I'd have to go back and look for it, might have been a forged Vs stamped lever blade? Makes no difference in use anyway.
The adjusters are for show only, I wound the bite point right to the limit and as close to the bars as possible 9not the limit, it'll pointlessly wind in furter). As I said they give a lot of power in not much movement, so good for running them that close. all my brake levers (avid, hope, shimano) bottom out on the grip while braking hard. I'd actualy rather they weren't there (save weight, les to hit in a crash).
Only problem i had with deores was a leaky nipple when i bled them and contaminated the pads, they turned into a squeeky non brake fest until i learnt a natty little trick of toasting the pads on an naked flame to burn off the brake fluid now brake power is better than ever!
I have recently gone from 2011 to 2013 XT's, with the finned pads. great brakes and noticeably more powerful thatn the 2011 versions, with same size rotors. Front pads click and rattle annoyingly but a minor niggle
