Korg AX3B and AX5B

Does anyone know, other than the expression pedal, if there are any major differences between the 2 units above. I'm sure I read somewhere (perhaps here) that the AX5B uses the same software as the 3000B, and the AX3B's software is of perhaps lower quality.

I'm currently fed up lugging a pedal board along with amp head and bass on public transport and wanting to go back to using a multi, it's just easier for me. I don't need a huge unit like my GT6B that I still have, just something small but with good enough essential sounds.

I tried the 3000B out today and liked the quality of the drive tones which are blendable with direct tone. The compression and chorus worked just fine for me and likewise the synth that I need for the odd disco tune. The filter isn't too bad either. But a unit that size is overkill for what I need, and the 3 and 5 will fit in my gig bag (well the 3 will anyway). I don't really need the expression pedal and the 3B makes without one makes it even smaller. If I really need a pedal wah I'll dig out my boss v-wah or get an external expression pedal later.

I have consisdered the zoom B2 too, but I haven't tried one yet. I've heard the drive sounds aren't as natural sounding as the Korg. Plus I liked the fact the synth and drive are in separate modules in the korg, allowing for a huge fat sound.

All comments welcome.