I also recently purchased the new Tivo Premiere box that came out earlier this year. It wasn't a conscious choice on my part to buy the new unit, but my trusty (and recently out of warranty) Tivo HD all of a sudden crapped out one day and refused to boot up. I'm almost positive it was a hard drive problem, and I'm sure that given some time I could have hacked into the Tivo and replaced the hard drive myself. I also had the option of paying Tivo $149 for a refurbished replacement, but that would leave me DVR-less for at least several days. That may have been okay under normal circumstances, but the timing of the failure couldn't have been any worse because it occurred right during the middle of the Tour de France! So unless I was willing to wake up at 5am each morning to watch the live coverage (NOT!) I needed a quick fix, and that quick fix was to just buy a new Tivo Premiere and get it shipped overnight from Amazon.
As usual, setting up the Tivo was a very painless exercise, and props to Tivo for making this as easy as possible for the average Joe. Getting things setup properly with Comcast is an entirely different story, however...as usual it took a couple of calls plus a lot of wait time on the phone before the CableCard "pairing" process successfully completed and I was able to access all of my channels - for some reason HBO always seems to be a problem.
There's been a fair bit of discussion regarding the new Premiere and how it differs from the previous generation of Tivo's. Quite honestly, the differences are relatively few, and so if you are a happy Tivo Hd or Tivo XL owner then I don't think there's enough new functionality to justify the switch. The major new "feature" is the revamped, Flash-based "HD" user interface, and quite honestly it is a mixed bag. If you have an older Tivo you probably have seen what this looks if you've tried the Tivo "beta search" feature, which lets you search for content not only within the Tivo guide but across the various internet sources that Tivo supports - Netflix, Amazon, YouTube, etc. The biggest problem with the UI is that it is incredibly SLOW...the system often hangs and hangs when switching between menus. And the UI is still not complete, i.e. some of the menus sport the new UI but a good number of menus are still using the older UI - making for a very disjointed user experience. There are two very nice things I like about it, though: 1) the Now Playing list (aka "My Shows") now displays the percent utilization on the hard disk for programs that you've recorded and saved; and 2) within some of the top-level menus you can still see what's currently playing on your Tivo via a small window on the upper right corner of the screen. I always found it annoying with the old UI that as soon as I hit the Tivo button whatever I was watching got instantly preempted...the new UI allows you to keep watching that program while navigating within the menu.
The other really nice improvement is the increase in speed when transferring content to or from the Tivo. I can now transfer HD content via PyTivo at a rate nearly equivalent to real-time, i.e. I can start viewing the content almost immediately and not have to worry about getting ahead of the file transfer itself. SD content has never been a problem, but with HD content you're talking 5x or so more data and the old Tivo just couldn't transfer data fast enough to keep up when I wanted to play something "on demand".
Hopefully Tivo will address the UI sluggishness issues before too long. The Premiere also contains a dual-core processor, but my understanding is that the second core has been disabled by Tivo due to some multi-threading problems that were encountered during testing. Perhaps if they can fix this and enable the second core that may help speed up the UI as well.