I have been running Dynojet's O2 sensor since March and absolutely love it. I had been pestering Wayne to address the issue with Tuneboy and was happy to hear that he made a great product even better.
So far as popping goes, you've got to get the bike custom mapped...period. My bike has a PC III custom map over Tuneboy's Jardine tune. The bike does not pop loud like it did before the custom map. It will sometimes rumble when I accelerate hard, then quickly let off the throttle, particularly if not 99% of the time in 1st. The rumble does not bother me at all. Those loud pops did bother the hell out of me - they sound like crappy backfiring I associate with junk cars, but that's just me. I've read online where some guys like the pop. To each their own, ya know.
From what I understand you can get your bike tuned to where it won't make any popping or rumbling noises, but I really think you will have a bike that is running a bit rich, which will cause some lag when accelerating.
I totally agree with what Pig9r and Doug are saying about the L-tables and the adaptations. Before I had the PC custom mapped, I made sure to get rid of all 0's in the L-tables. And if you're on a bike where the rumbling or popping is getting a bit beyond your comfort level, resetting the adaptations is something I gotta agree with.