I have had Oakley Half Jackets and just recently got a pair of Smith Parallel (the D-Max ones). The only thing I wish the Oakleys had was the hydrophobic lens for when I have to stop at a stoplight in the mornings and fog up my glasses. I haven't been wearing the Parallels long enough to see if that's a problem.

Interchangeable lenses is really nice in some situations - in the winter or if I ride at dusk, I can prevent bugs in my eyes by switching to my yellow or clear lenses. I think to zoom-zoom's point that photochromatics would be nicer and more convenient, but I haven't yet had a chance to try them. My husband switched to transitions lenses recently and really likes them.

The Parallels seem to fit underneath my helmet better than the Oakleys, but I can't yet figure out how to jam them into the top of my helmet to stick there when I need to go from riding to the elevator up to my office. Both fit my face pretty decently, there are so many I can't wear because I look like a giant bug. At this point I think I'd go for the Smiths before the Oakleys again just based on comfort and fit, but it's a little early.