After having many, many bluetooth headsets, i will never in my life ever buy another "in the ear" headset. I have seriously went though jabras, motorolas, nokia's and by far the most comfortable is the motorola ones that are out of the eat, ie. the one I use now the H700.
When they stay in the ear too long it starts to hurt, even the Jabra one I had came with 3 different attachments to fit your ear, but still none were perfect, so that meant after 20 minutes of use, i started to feel straining in my ear, and for an hour drive to work every day it just wasnt worth it.
Stick to headsets that dont fit into the ear, just my advice.