RayRay13000: So I recently bought Anno 2070 during a steam sale and now I'm wondering if I've made a mistake. I've never messed with uPlay but only heard of it and read some users experiences with it. Can anyone tell me in exact detail what I'm dealing with when it comes to this DRM?
In my experience, it's no worse than Steam's online mode. And that pretty much sums up what you are dealing with. Their version of Steam's online mode complete with cloud saving (depending on the game). For that matter, for most games using it, you only need to be online for a few seconds in order to authenticate during launch (again, just like Steam) and can then happily continue playing even if your net connection goes down for several hours -- any saves made locally during that time should be synced the next time you connect.
The only game I know of offhand that still requires being connected to their servers during play is Settlers 7 and that's pretty much due to the multiplayer/social focus of certain features.