Meh, I have both a Tivo HD and 360, and they are both problematic with Netflix.
The 360 version suffers from "one bar syndrome"; after a couple hours of watching, the quality slowly drops down ("your internet connection has slowed") to the point where you can't get over one bar and the picture quality is total crap. Even restarting the 360 doesn't remedy this, it's got to be something on the back end. I originally chalked this up to congestion on Netflix's servers, but then the Tivo version rolled out...
The Tivo version gives 8 or 9 bars out of 10 quality at all times. So much for the connection issue being on Netflix, it's obviously something on the 360 side. However, the Netflix version KICKS ME OUT OF THE APP EVERY FEW MINUTES, which is even worse than the quality dropping.
I realize that this service is in its infancy, but you'd think that they would do something to make it watchable, which it barely is on the 360 and completely isn't on the Tivo.
As far as interface goes, I call BS on the Giz article. The Tivo interface feels very "2002" - drilling down through layers of menus to get to the episode of the TV show you wanted, not having enough information listed on the layers to know whether you've seen a given episode, and dog-slow refresh times on the menus to boot. The 360 version is lightning fast, loaded with relevant information with a single click and feels like it belongs in 2008/9 with it's big side-scrolling coverflow-esque UI. And their BS about not being able to FF/RW? I guess they never thought to try using a real remote instead of a game controller, in addition to being too dumb to figure out the triggers. I've got a Logitech Harmony 360 remote to run my whole HT rig, and it works great with Netflix on the 360; there are lots of other options out there as well for a lot cheaper that would do the job.