Well. yes and no.
HD in terms of TV set HD resolutions .. yeah, they can both playback 720p no problem, however, it won't be nice with 1080i. Neither of them. And, there is the computer version of HD.. where the compression used (like H.264) will slaughter any laptop or low-end computer incapable of realtime decompression at 1080i. I should know. I have a brand new iMac (2GHz) G5 and it can't playback 1080i without jerky video in full screen or windowed mode! H.264 is just too demanding for the average Apple, though, a new PowerMac would play it just fine I'd imagine, due to better graphics cards. No idea about the Panasonic.