I have one of the old Pioneer gourd calabash pipes, and while it's not a clencher, it is fantastic for smoking flakes. Especially those Virginia's which tend to create a little extra condensation. Plus, it really helps eliminate almost all the tongue bite.
I've never tried one of the briar calabash, but I have been looking at some that have the magnetized briar bowls. I wish I could get a magnetized meerschaum bowl, but I haven't seen anyone offering any of those yet. I really like the versatility of only having one meerschaum bowl to smoke multiple blends with.