I have had 4 different HD DVD players (HDP5000, A1, A2, D2) and the early models did have freezing problems. But the current models (A2, D2 and other 2nd gen) are all A-OK, in terms of bootup, navigation, playability of titles.
I have over 30 titles and play many SD titles and its my primary player now (sorry Oppo, S301).
My S301 freezes and FF/REW is delayed response no matter how much I await firmware updates and hope that they solve them...not to mention disappointing picture and sound, compared to my A2 and Oppo.
You may want to try a firmware update on your A2 if you still have it.