I tried the Lightspeed Mach1 (a very similar idea to the Clarity) and found that it was liable to work loose and then one obviously got a massive amount of noise getting in.
Apparently this is a known issue unless one gets custom made earplugs for it.
I sold mine on U.S. Ebay (they were in short supply then) and stuck with the bose-x.
Have to say though that the M1 had the best mike I have ever used. Fantastic clarity.