I like Game Studio. I own two other commercial Engines.
I don't have Unity Pro !

But i don't say :
Hey , i failed to import a model on that engine, so it's trash really !
And sorry but lot of people make games each day with the engine : just browse showcase forums to see all games that are successfully made.
And people are 3D artists, so why don't they have your problems ?

And each engine can have bugs like ALL ENGINE IN THE EARTH !
An engine with 0 BUG DON'T EXIST

So come to a more professionnal level : MAKING GAMES !

- Step 1 : Test and buy the engine that suits your goal
- Step 2 : Make a game
- Option 1 : You tried another engine, but you don't like it
or you failed using it : No problem : leave it
or try again, or choose another 3D engine

But don't start saying some professionnal engine is trash when people behind is making a amazing work and with passion

Could it be Torque 3D, Ogre3D, the dead Truevision3D , LeadWerks Engine , C4 engine or other ....

I like a lot A8 , really, so easy to get into , and so much tutorials and great members community indeed

But well saying Unity is bad ... well ... it's an army of developpers behind, with really serious business and multiplatform, consoles , conferences, advertisments everywhere .... Well ...

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I tested UT3 engine, i don't have succed to import a simple model, texture was black ... i made it in 5 seconds in MED ,
so UT3 Engine is really buggy and bad

Don't take it personnaly , i have nothing against you, but learn to be relative, don't be hard with others.

They sell an engine, lot of games are made wih it, they have a demo !they have a free version !
You like , you use !
You don't like , you pass, they have nothing to do and zero interest with a customer that don't like their engine
They would just say :"Go and use whatever you like we have our own business to manage !)