For Gamemaker, you'll find little support, there is a member on these forums, zavix, I think, who might be able to help you out. Just look him up, he made some topics in the Work In Progress forum. I think Gamemaker should be pretty self-explainatory.
Oh, and BTW, never believe DBC isn't good enough to create high-standard games. Actually, some of the best DarkBASIC games are (being) made in Classic. However, Pro does offer some advantages over Classic, and Classic holds some pro's over Pro. So, just try both demo's and see.
Do remember though that DBC and DBP are truely programming languages. Grab the demo's and see if you can whip up something.