I have been running the Steam version of my game for years and it's fine. I've never heard anyone, who wasn't suffering from some other problem like a broken computer or had some other issue happening at the same time, claim that Steam is not a stable platform. I don't need to have Steam or the Launcher running to start the game, the Launcher bypass by way of a shortcut right to the exe file for TS3w works just fine. Once the game is up and running, it's Patch 1.67 just like any other on that patch level. It's possible that TS3 doesn't like some of the Steam overlays very much but since I rarely start up Steam in the first place in order to play TS3, I'm not seeing those issues.
The cut off and funny looking "fonts" you are experiencing is usually due to a slight mismatch between the resolutions of your game and your overall computer. I get these too on various resolution combinations and usually trying different ones helps to solve it.
