Game Creation System:
Took the Pie team a little less than a year to update, & if you were to read the news section, they changed the date back to about 4-6 months after they last posted (which was one year ago this month.) I wouldnt go with their system, it can only make First Person Shooters, but is great for those who cant program.
Dark Basic Pro:
Fairly easy to use, easier than A5 (3D Game Studio) & a heck of a lot easier than Jamagic (couldnt use it, had no clue what I was doing,) but not easier than the GCS.
The Games Factory/Multimedia Fusion (TGF/MMF):
About as easy to use as the GCS, but can only make 2d games, some 3d engines were made, but they were only a few poor examples, which is top of the line for that engine (we are talking about wolf3d & a cruddy version of star fox (SNES version, but looks like it was made with the NES)
Your best bet, if you know C++ or even Basic (DOS), I would use Dark Basic Pro, but if your totaly new, I would try something less powerfull to start you off, but from what I can gather, you know C++, so I would try Dark Basic Pro.
I learned programing in Basic & I grasped the concept of 2d games in it pretty easily, I just couldnt make them very big, as this was the second to the latest that I learned in, back when 95 had just come out, before that, I learned text based programing in Basic, which I could make a choose your own adventure game in it pretty quickly.