Epic’s Unreal Engine: There is a reason the vast majority of the gaming industry uses this engine to develop their games. It’s robust, offers a wide range of development tools, has a fairly short learning curve, and produces outstanding visuals. But, nothing is perfect. The engine is still based on the ancient BSP tree model. Couple that with baked lighting and iteration can become very cumbersome. While working on A:CM it took up to 2-3 hours to do a complete rebuild and compile of BSP, Lighting and Navigation. This is a huge hindrance on iteration.
Cryteks CryEngine 3: As you’ve guess, I’ve saved the best for last
I really can’t say enough good things about this engine. The first thing is no compiling!. Absolutely every light you see in game is either Deferred or Dynamic. There is no baked shadows or lighting. This by itself is enough to take the crown, but it doesn’t stop here. CryEngine 3 is NOT based on the old BSP Tree model. There is a tool within Sandbox that allows the user to create Solids (CryEngines version of BSP), but they require no compiling! All of this equals one very important thing - Rapid Iteration. While I could go on and on about other features, I do want to mention that Flowgraph is by far the most powerful scripting GUI I have used. It lacks a few key features that Kismet (UnrealEd) has (such as Remote Events Print to Screen debugging). But this is compensated for by the sheer quantity of operations provided (Math, Vec, Int, String, etc). This gives the scripter literally all the tools they need to do what ever your crazy mind can think of.