wolfsrain: My advice is get UPlay games on UPlay. You don't really want to clients running at the same time.
You will have to:
1. Create an UPlay account
2. Download UPlay
3. Start the game via Steam
4. Launch UPlay
5. Play
With UPlay you start the game via Uplay and you can put it in offline mode. With Steam version you will have to keep both clients running and be online....
So, if you really want a game that is using Uplay, buy it via Ubi store. Forget Steam.
Personally i prefer to have the Origin/UPlay games on the respective platforms.
^ THIS
^ I know from first hand how annoying it can be running a "SteamUplay" game. Steam doesn't track gameplay time all the time, it won't update or don't have the same version, Uplay patches are incompatible, if file integrity is checked it will redownload almost all the game again with the same files (same CRC), the game "will jump" from to client to client when is started... arghh (>_<). I only have 1 game that has to use both platforms (Far Cry 3: Blood Dragon) but after all that experience, I've been buying all my Uplay games for the Uplay platform only.
Yes, Uplay is strange, you have to download the first version of the game, then it downloads the patches one by one during the installation, and the DLCs have to be downloaded separatelly as well, like installing the game from discs. But it's easier and no more Steam issues in-between. You can also backup the installers later if you want.
What I learned: Buy the Uplay games for the Uplay platform only, never mix Steam with another platform/client ever again.
( Although, when finally Blood Dragon was running properly it was great ^_^ )