Unreal engine is probably the winner here, it's very powerful but also the development tools are pretty much the best in the industry.
Cryengine is also very good just as feature complete as Unreal engine maybe more so, pretty good development tools.
Source engine is old and crap and the development tools are atrocious, the updates it's received over the years are minor at best. The whole thing needs scrapping or a major re-haul.
idTech engine is really more tailored towards specific game, it's megatexture is quite unique but so far only really used to boost the memory issues with consoles and not to push the high end.
Frostbite I don't know a lot about, aimed squarely at consoles with what feels like DX11 a bit tacked on, not sure about development tools.