Yeah, you'll find encoding and reencoding kinda fucks with quality quite a lot. I'd recommend using the "Startmovie TGA" command from the console of TF2, and if I understand it correctly, it works like avi_demo on CoD games, just takes lots of screenshots (don't know if you can specify the FPS like you can in CoD), which you can then stitch together in VDub (I recommend outputting to uncompressed AVI) and then you should edit it in your editor of choice (I'd recommend Sony Vegas) and then output as WMV, I find that works quite well with Youtube.
There are limits to what you should do with editing, like Zeek said, lots of effects and flashy transitions are kinda a turn off imo. Keep it simple, with popular music, well-sync'd, and subtle effects, that don't detract from the actual footage.
There are limits to what you should do with editing, like Zeek said, lots of effects and flashy transitions are kinda a turn off imo. Keep it simple, with popular music, well-sync'd, and subtle effects, that don't detract from the actual footage.