I have decided to make the switch. Yes, a new media center (or HTPC, if you prefer). I've been a longtime follower and user of MediaPortal, both for its ability to run on different hardware and the quality of the finished project. It has the ability to run a TV "server", and schedule recordings and playback for every MP computer in the house. In addition, it has great plugin support and the quality of the plugins are just as good. That said, I'm switching to Boxee.
What I want out of a media center is: ease of use, ability to play local files, TV & movie thumbnail/synopsys integration, streaming radio, and a professional look. Both MediaPortal and Boxee fit the bill on all accounts, but where Boxee takes the cake is the ease of use. This isn't just for general ease of use, but for my ease of use. I've got two $20 MCE remotes that have drivers for Vista-only (and linux). They just won't install on XP.
So when I upgraded the latest version of MediaPortal to Vista, I found out that... Vista does not like MediaPortal. For whatever reason, it takes 10-15 seconds to start a video. In Boxee, on the same hardware, it's instant. I've also had a few MP crashes since installing, mostly due to plugins not being available for the skin. That one irks me, because a skin/theme should NEVER throw up an error if it can't find a plugin.
Also, the iPiMP plugin is MediaPortal's iPhone-integration "app". I use the quotes, because really it just serves a webpage with MediaPortal-specific functions. This works, but every button press results in a refresh of the page, which is very inefficient for performing functions such as volume up/down and moving between menu screens.
Boxee, on the other hand, has a native iPhone app, which does not require a page refresh every time I press a button. In addition, any search functions trigger the keyboard on my iPhone, making searching a LOT easier. This is important because my wife and I both have iPhones, and I can see that becoming a big feature in the future.
Boxee also has TONS of integration with streaming TV through Hulu, NBC, SouthParkStudios, etc. This is a minor feature, as I keep most of the shows I watch local. What does blow me away, however, is that if my local files only go up to, say, episode 15 of a series, and the current show is episode 17, Boxee will fill the gaps with the streaming versions of those episodes. That right there is pretty awesome.
I am also contemplating purchasing MLB.tv for the next month. This will give me access to watch my A's from anywhere, including my iPhone. The coolest part about this is the agreement and integration Boxee has made with MLB.tv. Now to watch my A's I can stream it right to my TV without having to drop down into the computer. This isn't a feature that the wife will find as useful as I, but it's still cool nonetheless.
So while MediaPortal covers my needs for an HTPC, Boxee covers it better. I'll still be tracking MP to see how the development of MediaPortal v2 is coming, but v1 just doesn't hold up to the Boxee beta.