That depends on that genre of games you wanna make. If you wanna make Fps games then you should REALLY go for FPS Creator. I have both 3D Game Maker and FPS Creator, and fpsc gives you SO much more freedome! It got physics, scrips, lightmapping, and much more freedome for making levels! While 3D Game Maker is much more limited. It works as promised, but the results aren't really that good
Also you can sell the games you make with fpsc, without buying any license. While you would need to pay atleast 100$ for selling 1 game made with 3D Gamemaker... And 500$ for selling unlimited games made with it...
Why don't you go try the trial version of Fps Creator?(If you haven't done that)
-The Nerd
PanzerGames
here
Free Particle Engine For dbpro :
here