Lost 6 hours worth of Deus EX Human Revolution saved games, fortunately managed to recurva most of them back off the local HDD. Put simply when prompted to use the most recent copy, which was on the cloud, don't click anything until you check the local files yourself. The cloud might be wrong 
How to do this:
1. Find out the appID of the Steam game you want to check by doing this (taken from Steam page)
2. Using this Appid navigate into your Steam folder then into the following path:
\Steam\userdata\<userID>\AppID
If the dates and times of the files within that path are more recent than those displayed for the Steam cloud, use the local copy - even if Steam insists that the cloud files are more recent.
I chose to use the Steam cloud copy as it clearly stated that the local copy was 3 days out of date, however after running Recurva I've now got ones which are far newer and have manually inserted them back into this folder to restore them.
Personally I won't be turning Steam Cloud off on my games, it is useful but when there's any problem syncing back to the server it appears to assume all that local files are all older than the LAST successful sync, rather than actually comparing the individual file dates with those in the Cloud. So the next to time launch the game it presents you with a pop up claiming your local files are older, when they could well be more recent.
May seem trivial, but as some of us have dozens or even hundreds of hours invested into these games it's perhaps worth knowing.

How to do this:
1. Find out the appID of the Steam game you want to check by doing this (taken from Steam page)
- Login to the Steam account
- Go to your Library
- Right click the installed game and choose "Create desktop shortcut"
- Go to your Desktop and locate the new shortcut
- Right-click on the shortcut and select Properties
- Look at the target path for the number following steam://rungameid/. This number is the Application ID for the game.
2. Using this Appid navigate into your Steam folder then into the following path:
\Steam\userdata\<userID>\AppID
If the dates and times of the files within that path are more recent than those displayed for the Steam cloud, use the local copy - even if Steam insists that the cloud files are more recent.
I chose to use the Steam cloud copy as it clearly stated that the local copy was 3 days out of date, however after running Recurva I've now got ones which are far newer and have manually inserted them back into this folder to restore them.
Personally I won't be turning Steam Cloud off on my games, it is useful but when there's any problem syncing back to the server it appears to assume all that local files are all older than the LAST successful sync, rather than actually comparing the individual file dates with those in the Cloud. So the next to time launch the game it presents you with a pop up claiming your local files are older, when they could well be more recent.
May seem trivial, but as some of us have dozens or even hundreds of hours invested into these games it's perhaps worth knowing.