I use XBMC with WMC. I wanted the Metadata and Cataloging of my TV Shows and Movies like Mediabrowser but I wanted to also add Console Emulation and Streaming sources and be centralized.
Linux Live TV is half-baked. Supports Tuner card only with friendly Linux drivers. This is fine if you're starting from scratch but it took up until the last version of XBMC before Eden to support hardware acceleration for newer AMD chipsets and GPU/APU's. As I said in the Linux thread, doesn't work with my current set of tuners. = No Go
WMC just works, setup and go. It just looks rather dull and metadata it keeps is just okay, it will only display metadata for what it recorded. No posters and no fan art. Isn't that why people use Media Browser in the first place, the eye candy?
The Recorded TV solves some of this for Recorded TV on WMC, but at a cost ($30). Second Run TV 2.6 adds streaming content for $4 but I like the You Tube add-on for XBMC. Access to Subscriptions, My Watch Later and its set to only show the best quality content, IE no 240p or whatever unless that's the only version of the file available. Marks content already watched, fantastic!
The important thing to remember with using MCM or the another scrapper is (even MB) is folder/file structure. Otherwise, metadata will get knackered and you'll get strange links to theTVDB, TV Rage or IMDB.
Also instead of adding all these codec packs to Windows Media Center to play say MKV's why not just play them back in XBMC? No codecs, works by default.
Now if I can only get the "Info" button my MCE to work as the "C" button in XBMC and still have standard WMC functionality outside of XBMC....
I just finished messing with my folder structure to fix any errors with Advanced Launcher.