I put in a clip from my HMC150. With 9, it *is* better, but if it has problems playing back at full rez, it will simply default down to half rez to playback more smoothly.
I have the equivalent, HMC 151 (PAL).
I noticed the same, playback is always smooth because it somehow detects the fidelity and adjusts accordingly. Huge improvement!
Much improved! The MP4 files from my Sanyo HD2000 (1920x1080 60p) play nearly realtime in the preview with some stutters. Transitions are still bad though.
With Vegas 8.0c these same clips played back at about a terrible 2fps!