I've got a Korg Pandora PX4D and I use it a lot. Even more than BIAB.
The thing I use most is the PhraseTrainer/Jam Function mostly with
the Jazz, R-N-B, & Bossa rhythms. It's neat to be able to quickly
play & record a 1, 2, 4, 8, or 12 bar accompaniment(up to 30 seconds)
that automatically loops back allowing me to immediately start
brainstorming & practicing solos, lick ideas, cell patterns, etc. I
now hear more and connect certain chord tones & fingerings with
certain beats & rhythms. Also, hearing my own comping playing back
has forced me to really clean up my chords and timing. I'm trying to
work a PX5D(Jams up to 80 seconds) into my budget for next year.
Finally, you don't have to limit yourself to headphones. I've run my
Pandora into a Guitar Amp, my Computer's microphone input, my stereo,
... a small pair of computer speakers. The Pandora's flexible &
extremely portable.

- gaigin53