We really need to know what you will use GStudio for (yeah I know, games )so that the best recomendation can be given.

Going Standard and Lite-C =
Standard= No terrains, Bones or advanced mapping
Lite C= No World editor

Extra= not sure about

Commercial= everything you need to make games.

Professional= Same as commercial but with extra goodies to complete any gaps in the whole process.

Languages
Lite-C (Wdl and c_script phasing out)

Hopefully users with more clues will follow up.

Cheers...