I'm a big fan of the CryEngine, I've worked on multiple projects in the past; namely Ryse and Streets of Rage.
Drop in/out of game is super fast as are the iteration times. I find level design much better in this engine than any other. It also shares a lot of similarities with technology used at Ubisoft, so I'm rather biased ;)
I've also used Unreal for a couple of projects, including the open world title, Wheelman - it was really quite flexible and Kismet is a neat scripting tool (I prefer it to CryEngine's Flowgraph). Some of my pals are working on the new Unreal Engine and say it could be world changing for indies - but then they would say that, wouldn't they ;D
I've used Unity a couple of times for prototypes and game jams but I find it a little cumbersome and surprisingly unintuitive - though most would disagree.