I have the Hobie convertible harness as well. I love it with one major exception - when you're doubled over to get under the boom on an H-16 or H-17 (especially the 17), the rear "plate" sticks out enough to catch the boom as it goes over your back. It also interferes with the "skirt" on some of the PFD's I wear, contributing to the problem of the PFD riding up.

I went to a MM full harness in 2005 (not really thrilled with it), and just bought a MM half harness last weekend. The new half harness is nice, but the jury is still out. One day of sailing is not enough to judge.