The Xbox 360 Fall update was released on November 1st, 2010, and brought with it a new visual look and feel, based on the Metro UI which originated on the Zune and has since been used for Windows Mobile 7.
As such, I understand where Metro is coming from: it's been designed for a small handheld device with a touchscreen interface, constrained memory, limited processing power and relatively low screen resolutions. In this context, a high-contrast colour-scheme makes perfect sense, as does the decision to have minimal visual "clutter" - and after all, you're either looking at a fullscreen application or a set of icons.
I even understand why Microsoft is trying to push this one UI across all of their devices. Consistency is generally a good thing and they're competing with companies (Apple, Sony - plus Nintendo and Google, to a lesser extent) which have this down to a fine art.
But the Xbox 360 isn't a small handheld, single-tasking device. It (generally) runs at a higher resolution[*] on a physically bigger screen and presents a higher level of information density. It's also not a touchscreen device.
So far, I'm finding myself actively disliking the new Dashboard, for several reasons:
1) it's harsh on the eyes, with it's high-contrast colour scheme (e.g. white boxes on a black background, or the all-pervasive white/green pairings)
2) the lack of borders means there's often limited visual separation between items
3) the animation feels stilted and jerky: when reviewing a game list, the icons seem to lurch forward before sliding to one side.
4) There's generally minimal indication that a view is scrollable - the "game details" view is particularly bad for this, as the only indication that there are multiple pages of information comes from the font-colour at the top of the screen
4) When you look at a game for the first time, the default option is "buy now", not "Try demo" (though to be fair, I can't remember what the old Dashboard's behaviour was!)
5) You can't rate games from your game list; instead, you have to do it from the catalog
To be fair, the old Dashboard had its fair share of problems and there has been a few improvements. For instance, list scrolling speed is capped, so you don't end up zooming through several hundred titles in a fraction of a second, thereby missing the one you actually wanted. And the interface does feel a bit more responsive and snappier in general. But (at least for me) these are more than outweighed by the negatives outlined above.
(There's issues with the similarly themed xbox.com website, too - for instance, the game's description is hidden by default and you don't get any thumbnails for the screenshots. instead, you have to manually click around the page to find out any useful information on the game! Though again, at least they've vastly improved the search and sorting facilities...)
Overall, I'm curious: what do other people think?
[*] As of 2007, a Neilsens survey indicated 70% of gamers were using a HDTV: I'd expect the numbers to be higher by now, given that it's nigh-on impossible to buy a non-HD tv now!