It really depends on what your game/team needs. If you're trying to make a match-3 then Unreal is maybe not the best choice. If you're trying for competitive cutting edge graphics in an engine that is mostly done so you can actually focus on the graphics, then Unreal is top of list.

I think its probably better to look at Unreal as state of the art but licensable. Other big game companies have cutting edge engines but they're proprietary and not available to license.