Now, I love everything about the bounty hunter. Boba Fett, rockets, flamethrowers, jetpacks, attitude, more flamethrowers. I actually enjoy tanking, and PvP. I can do all of that with my powertech, and grapple is one of the meanest things out there.
Flavor wise, I love AP. retractable wrist blade, heat being non issue, ect.
Pyro does great amounts of dmagage though. Everything I have come across says pyro outstrippes AP by a wide margin, so I went pyro. EVERYTHING is on fire. Always. And it makes rail shot hit like hell, and you'll be proccing free railshots every 2-4 flame/rocket punches. Free means that unless youre taking on mobs back to back to back, or cant seem to get killed in PvP, heat isnt an issue.
I'm not a number cruncher, min-maxer, or the best around. I havent given AP its fair shake yet, but that is my experience with it.