I unlocked the Kritzkrieg for the medic in TF2. There are three more achievements I'll get without having to cheat. The other ten are hard enough that I'll either need a lot of luck, or to cheat. I do want that ubersaw, so I may cheat it up.
I'm just not sure about the Kritzkrieg. Getting all crits is nice, but being invincible is so much nicer. There are too many times where I've had to take out two turrets, and there's no way that a person could survive that without being invincible. It charges faster, but that's the only other benefit. I think I'd be for it if it healed faster or something.
I'm selling my XBOX 360, since I need the moneys. I could make a brief comparison between TF2 on the computer and on the Box:
Cost: free vs. monthly fee
Updates: free vs. none at all
In other words, Live costs money, where the internet on a computer has no additional charges. Winner, Internet.