Quote: "Quote: "You are going to try and argue that Source is bug free? "
Show me something better"
TBH, in my experience, games made with Unreal have been more reliable. The only Unreal Exception is the XBox 360 version of The Last Remnant, but only because Square Enix did a half-assed job on the optimisation. PC version, runs really well. SE's fault, not Unreal's.
Source games, I've always found trouble with Counter Strike: Source, hence I don't played it. Half Life: Source runs well, Left4Dead had some problems with optimisation, I used to find on my old laptop it'd go really slow after a while although nothing seemed to have changed in terms of what has to be processed and the laptop wasn't overheating either. Half Life 2 & Portal, works well, though they seem to stutter at times, but nothing major. Portal 2, I had no problems with it on my 360.
However, I'm sure others have found Source to be more reliable...I think people's experiences differ. Source is a great engine, but I wouldn't exactly call it bug free. And in my experience there have been engines that run better, however, I couldn't actually name them because they were probably only programmed for the specific game.