There can be only one leader when it comes to game engine market. And that leader is now Unity. Unity’s official website
Statista states that Unreal Engine is the second most popular 3rd party game engine in the United Kingdom after Unity. While Unity got 62 percent of the total votes, Unreal Engine was not that good with only 12 percent.
There are several keys to this success. It has lots of benefits: low learning curve for beginners, active ecosystem of asset and plugin creators, rapid development speed, and its cross-platform integration that supports 25 platforms – UE supports 10 platforms and CryEngine only five. That is the reason for the love from its 4.5 million registered developers.
Unity also gives access to 15,000+ free and paid-for 3D models, editor extensions, scripts, shaders, materials, audio, and animations.
Source: thenextweb