FPSCreator is much closer to the Game Maker software that you have been using than Dark Basic and Dark Basic Pro.
The two DBs are complete(ish ^_^) programming languages. There is nothing 'drag and drop' about them. You start with a complete blank slate and have to program line by line, coming up with code to do everything....and I mean
everything!
e.g. You'd need to write code for:
Reading input from the user and dealing with it
Loading the levels
Collisions
AI
etc.
The forums are a great source of help, but if you don't have a mathematic and/or logical mind, and you just want to create an FPS, I'd go with the creator.
That said, personally I love the DBs for their flexibility!
"You get what everyone gets, you get a lifetime!" - Death, The Sandman Library
First you Dream, then you ... - Neil Gaiman, 2001