Going from plain old platforms to clips was like night and day for me. I haven't used clipless pedals extensively, so I can't comment on them, but I like clips so much I don't see any need to switch to something else (at the moment). Once you learn to "kick in" efficiently, the low BB shouldn't be a problem. If you do decide to go with clips, make sure you get a good quality pair of metal ones; in my experience, the cheaper, plastic ones aren't even usable. I've never been able to try leather straps, though, because I couldn't find any long enough for my big fat feet, so you'll have to consult someone else for the leather vs. nylon debate.