From the viewpoint of a professional programmer, which I am as I earn my money with programming, Gamestudios main advantage is the engine API and lite-C script. I have found in no other engine this possibility to write some little 3D app that almost instantly works, in a couple of minutes. Especially with A7. A7 was a big step from A6. Also shader programming is very powerful, much faster than with any other engine that I tried, because of the shader building blocks that you have and the fact you instantly see the effect of your code on the screen while you type.

For quick solutions that do not require lenghty level design Gamestudio is unmatched IMHO. Another advantage is that the engine improves permanently, updates are more often than with most other engines, a couple of times I found that I requested a feature and it was there two weeks later.

As a professional programmer you have to deliver solutions fast, time is money, thats why Gamestudio is my favorite tool for 3D apps until another engine comes out that offers the same fast and easy programming, but I have not seen any yet. When you compare it with vehicles, Gamestudio is a fast motorcycle and Torque3D is a heavy bus. Sometimes you need the motorcycle and sometimes the bus but when I had to choose only one I would take the motorcycle.

That said, there is one big disadvantage of gamestudio and that is that its not a studio. The name is misleading. Its not good for click-together kids and not good for only-artists. The editors are merely converters and the templates are not good. In fact the templates are awful. You can not really do something useful without some programming. This is a big marketing fault and I think its the main reason of complains of disgruntled kids in threads like this. They have no clue and just bought the wrong product. Gamestudio is ok for kids when they have some understanding of 3D engines and are willing to enter programming. If Gamestudio wants to become much more popular they should not put more features into the engine, but at first make better templates for many sorts of games.

Just my 2c.