Portable options

I'm looking into getting something I can grab and take with me to play around with and come up with ideas while I'm away from home. Currently, I'm looking at the Roland P6, Teenage Engineering K.O.II, Novation Circuit Tracks, and Ableton Move.

I use Ableton at home, so the Move definitely is appealing, since I can just take whatever I come up with and send it straight to the DAW, which isn't an option on the others (as far as I've seen, but I could be wrong). But it's also the most expensive. And being able to use the Circuit to control other gear could be fun in the studio as well.

Any recommendations? For what it's worth, I mostly make sort of ambient/experimental/post-rock/new wave sort of stuff. My biggest influences are Sigur Rós, Radiohead, Nick Cave and the Bad Seeds, and Lambchop, in case that affects the decision. And I'm open to other suggestions as well. There may be something perfect for me that I'm not aware of. But I'm trying to keep it at around $500 max.