Hi.
I have been used for years unity3d. and learned c#, javascript.
and launched humble 3 games until now for mobile.
and want eventually earn money from mobile market to maintain me, furthermore my team.
Do I need to migrate to unreal4?
unreal4 only support c++ for scripting language?
What are more good points and what is more bad than unity?
Hi,
I suggest you visit Unity’s Gossip forum and read the UE4 thread (http://forum.unity3d.com/threads/235141-Unreal-Engine-4).
It’s about 80 pages or so, but there should be enough information from all posters to start forming a direction for yourself and your team.
My handle there is the same as here, and as you can see I’ve made my choice to switch to UE4. 
I don’t think you should other people ask whether you should do, or not?
Instead you should ask yourself what you want to achieve and compare the engines, based on your own needs.
The idea here is really to see where each engine will take you in the future, instead of focusing on what it can do right now, because you are investing your time and resources into it for the long term.
As I wrote in that UE4 thread on Unity’s Forum, I believe this is where the real “democratization” of gaming will happen, and not with Unity, as they originally promised.
Epic has done such a monumental change to the landscape, a paradigm shift if you will, the echoes of which will be heard long into the future.
The power of community that will gather here coupled with the availability of engine source code, will take UE to a totally new level, a magnitude of power higher than is now. I feel that Unity has missed out on that, but only time will prove me right (or wrong).
I knew this question would appear on the forums after time. When it comes down to it, there’s a fundamental difference that justifies why UE4 has a moderately steeper learning curve, and the way I see it is that Unity while it is a very good engine is Indie, UE4 on the other hand, is a AAA game engine.
With that said, learning UE4 from Unity will seem a little harder at first, but UE4 is much more improved over UDK. There are plenty of reasons to switch from Unity; Licensing, Graphics, Gameplay design with Blueprints, Modularity, and of course it has more features than the current build of Unity 4.3 that Unity 5 is trying to achieve.
Regardless, it all comes down to the simple idea that time is money, if you’re developing a game with a small studio or even by yourself, and you’d like to get your game out the door as quickly and as efficiently as possible. Then use the engine that supports your workflow for that given project. For example, Up until UE4, we made the decision to develop one of our titles on Unity because Web Player made it prevalent for that specific job, while our other titles were developed on UDK.
So when it comes down to it, learn both engines thoroughly, then make your decision as to which engine provides the best cost effectiveness per a given project.
That’s my two cents,
I think the best thing you can do is to try it by yourself. Pay just 19$/€ and play with the engine, download the examples, look at some video tutorial. There is no better way to know if UE4 is what you want/like than play with it by yourself. 
UE4 having source code is big game changer, it’s future looks very bright and strong. But it’s still new, it has bugs, unfinished features, lacks documentation and community.
So I suggest like Epic Games, that you wait 6 months for things to pan out. In that time, you can pump out 1 or 2 mobile games with Unity.