i've found that it's easiest to get out of the those pedals at the bottom of the stroke. also, if you're having problems clipping in, just freewheel your clipped shoe back to the top of the pedal stroke and start over, after or two times you should be able to clip the other foot in...

the thing about SPD SL's is that, like Look's, the pedal will always be in the same position when you're unclipped. so, after a few rides of getting used to that, you will be able to do it in your sleep...