Ok, so just put 15 miles on them this morning.
First thing is my usual ride involves 2 miles or so of road to get to the off road so to speak, and from the moment i set off i noticed the difference in cadence, its not massive but noticeable. Because of this i would be reluctant to go shorter than the 160mm. If you purely ride off road you may not be bothered by this.
However the moment i hit the off road, it was no longer noticeable, mostly because on the road i am usually just under or just over the cut off for the motor, and spinning a constant cadence, whereas off road i only hold a constant cadence for shorter amount of time, and if i am holding a constant cadence its on a steep uphill at speeds well under the cut off.
Once off road these make a big difference, i deliberately rode down and up the roughest parts of single track which are very rooty, with lots of run off channels cut into the clay by the water that makes up most of the tracks round here, and i didnt have a single pedal strike today. I would say that since getting the bike i have modified my riding style to minimise pedal strikes, but by about half way round my loop i had a new level of confidence in the bike, and was charging everything.
Also loved the crank brothers stamps, big improvement over my Nukeproofs. I went for these because i figured the large pedal platform would help off set the reduced overall peddling platform from the shorter cranks.
I have no technical data to back this up, but the Mirandas felt stiffer than the stock cranks too, and felt more efficient. They are less hollowed out than the OEM cranks.
All in all i would have no hesitation in recommending these cranks to anyone suffering from pedal strike! Bare in mind you will need to raise your saddle height to offset the drop in crank length.