Compared to Gamestudio the job market and the supported platforms are my sweet spots. There`re a lot more perspectives if you`re a good Unity developer or designer. It`s kind of an indutry standard and many (also German) companies are working with it. On the technical side the editor seems to be very powerful because of many advanced features and drag and drop capabilities. The programming part is a bit "crude" because of the component-based scripting system, but I`m not really into this at the moment.

I preferred Unity3D over Unreal Engine, because of the license trouble and the fact that I`d have to learn UnrealScript, which is useless in my eyes. C4 would have been an option if the community was bigger (TML seems to be the only German developer working with it).