Spy. Love the spy, and I can't wait to see how the mechanics of those new watches work. Some of the finer points, yet the most important ones, have been left out by Valve.
Dead Ringer - Does it show the upper-right hand corner kill sprite for the person who "killed" you so they really believe it? If not, this watch won't be worth much more than a half-second distraction. That could be nice, but not in exchange for my normal cloaking device.
Cloak and Dagger - How much charge do you get standing still while invisible? Do you break even, like when cloaked on a level 1 dispenser? You neither gain nor lose cloak? Or do you really GAIN charge when standing still invisible? Otherwise, it seems like the perfect balance to have the spy uncloak to gain the charge back, forcing him to be visible for at least some short time.
The sniper stuff is a little more straightforward. Though I'm still really disappointed in Jarate. I got a giggle out of it on April Fool's, cause it was so juvenile and silly. While TF2 can have some good humor in it, that's just a bit much, it really makes me feel guilty for playing a game that lets me throw pee on people.
What's next, Valve, flaming bag of poop bombs for the demo? When the enemy comes out of their base and tries to step on it to put it out, they realize it's full of poo...but not just any poo, EXPLOSIVE POO! Then it explodes and anyone with any poo on them dies!