got a front one last week, seems like a standard shimano type caliper with servowave lever. lever is not the nicest looking, but it fits with shifter pods MUCH better than the old shape lever as the bolt head is at the top, rather than under the lever (previously I had the saint m800 and the levers were terrible for sitting close to shifter pods.)
The lever feels very spongy compared to the old saints, but i think that is the servowave system, the tool free reach adjust works very nicely.
regarding the extra clearance, it is better but is not massive. with 1/3 worn shimano pads and a very slightly warped rotor i got the brake set up with only a tny bit of rub. but it was definately quicker to get right than m800 saints.
The setup i have is a hayes 203mm rotor that i power sanded before fitting the slx brake (it got mildly scored before so sanded it smooth again) and a set of sintered pads that i rescued after getting covered in oil. So a far from perfectset up. However, even with slightly dodgy pads and a rough rotor it bedded in fast and after 2 rides is powerful and the spongy feeling is lessening as the pads bed to the rotor.
with new pads and a proper rotor i think they will be very good brakes.