If I had known how perfect the MPC would be for my musical vision, I might have opted for the Live II instead of the One+. The battery, speaker, form factor, and second internal drive aren't compelling to be individually, but in aggregate, I'd find them useful.
Theoretically, it's not too late to take advantage of Guitar Center's 14-day no-questions-asked return policy. But seriously, I'm happy enough with the One+. Also the very thought of going through all that retail rigamarole fills me with a profound sense of boredom that I can't quite explain. Anyway, I've grown fond of this panic-button-red thing, and my view is that an MPC One+ is probably the biggest bang-for-the-buck in music production.
Once I was satisfied that it would do what I bought it for, I started playing around with things I never thought I'd appreciate, like the XY pad, resampling, the Looper, Clip programs. This weekend, I'm going to spend some time with CV.
Right now I'm at the point where I think all I need is Finale, my Prophet 5, and an MPC.