Here are some details of my testings.
1. Playing live on a record enabled midi track works great until i actually arm a clip and start recording. Then timing goes to hell.
So, it seems that the USB akai plug works well, but when combined with Live's recording function it glitches out. Note; I tried record quantization and without. Both sucked.
2. Use USB cable to power MPD 16, but route a midi cable into another midi interface and choose this midi input only for recording from MPD. Everything works great. The velocity and timing is superb. I finally do not regret selling the MPC 2000!
Gear; Powerbook G4 867MHZ, 1GB, 80GB, M Audio Quattro, Mbox, MPD 16,Niche Automation Station, Korg Z1, Juno 106, Moog Rogue, Waldorf Micro Q, Dm5.