Update
I just got my Pace replaced with a DCX3400 yesterday, and even though it's only been about 19 hours, I LOVE IT!! It seems way more responsive in everything you do (even scrolling through the guide), and it doesn't seem to have any of the issues the Pace had. I was all worried about losing the full-screen guide and hardware zoom, but it took me all of 5 mins to get over the guide, and I programmed the # button on the remote to control my TV's aspect ratio, which basically does the same thing.
I don't even care about all the recordings on the Summit I've lost, because it's so nice to finally have something that works! Shaw recommended formatting the harddrive on the Pace to try to fix the 1-min recording problem, so I would've lost everything anyway. If I had any idea of how much better the 3400 seems to be, I would've tried to get it replaced a loooong time ago!
The only current issues I'm aware of with the 3400 is the handshake issue with receivers (which I don't use, so couldn't care less about), and also when pressing the Info button while looking through your Favs list, it goes back to the beginning of the list when you press Info (or Last) again. I'm sure the Fav thing will be fixed soon anyway, but it's not something I care that much about either.
So in my short experience so far, the 3400 is ten times better than the Pace ever was! The expander works with it too, so I reaaaaaaaaally see no reason anyone would ever want a Pace. I think Shaw will give up on them pretty soon if they haven't already...