No more monthly subscription cost. You do still have to pay royalties as before (5% after making $3000 in a quarter). But hey, release your game as free/open source and you never pay a dime. Likewise if your game is a commercial flop, never pay a dime.
I've been a big fan of UE4 myself for making 3d games. Power and speed of C++ as well as a vastly superior editor, especially with that shader editor. It's not great for mobile games, mainly on older devices, as it uses deferred rendering on mobile as well instead of something simpler like forward rendering which Unity uses.
But hey you get access to the full engine source code on github. I've never attempted to modify that source myself, but I have implemented other people's patches into my version of the editor to save some headache before Epic got around to releasing a hotfix or point release.
And now because the UE4 is free, you can also poke around with the new Unreal Tournament for free.
Also UE4 supports 2d... but it's worse than Unity's offering (which I already thought was overkill) and certainly not as easy as something like ENIGMA.