Uh... several people seem to have good reasons to not recommend Unity or UE, but to put the truth right here:

On Gamestudio there is not much activity anymore, as Zorro was priorized. There are rumors that the next bugfix is quite close, but nobody has seen it yet.
If you have experience with Gamestudio and are not planning for a huge game binding you for years - go ahead and use Gamestudio.

Other than that, I cannot recommend its usage as long as the future stays this uncertain. We all would like to tell you something else, something better, but at the moment that would be a straight lie.