FPS Creator is definetly worth it. I wouldn't call it insane, but with the updates TGC is churning out left and right, they really
are trying.
But, like (insert name here) said, it's not all fun and games. When you really get to see and get used to the product, you'll find yourself tweaking and making scripts rather than testing your game more often. If you want your level(s) to look nice and (almost) realistic, then you'll have to put in AT LEAST 1.5 weeks' worth. Trust me, I'm a veteran.
Also, there are 6 model packs & 1 sprite (decal) pack, which are worth $120 if you get them all.
My final piece of advice is: if you want it, download the 30-day free trial first, then if you want more, get FPSC's full version. You can get it from FPSC's main site for $50, or (as I've done) get it from Amazon.com or eBAY.com, for around 55-65 USD. It depends on if you're ready for the frustration, sometimes happiness, and pure almost-wanting-to shoot-your-PC-with-a-shotgun violence. If you are, then GREAT! You're 1 step away from creating an OK (emphasis on OK), new-guy game. If you ain't, then get it anyways!