I'm playing through it right now. It's pretty funny, but it's still a fairly standard hack and slash game actionwise. I'm only about eight hours into it, and it's interesting. I've heard it's relatively short though, like twenty hours.
It's funny, I didn't even know Brian Fargo had anything to do with the game until a couple days ago. And the name didn't even register until yesterday. Now that I know that, you can definitely see some Fallout influences in the game: the stats, the choices early on that affect the game later, the humor...
I got it for free in Gamestop when I bought two other games (KOTOR2 and XMen Legends if you care). It's enjoyable so far, so I'd reccomend it.
edit- OK, I just beat the game. Friggin hilarious ending.
It's basically a more or less standard hack n' slash game like Bauldar's Gate: Dark Alliance, but it's infused with alot of humor poking fun at games like those. It's funny, but not so slapstick funny that it gets in the way of gameplay (i.e. it's not just a "joke" game).
If you like hack n' slash games, pick it up used. Otherwise forget about it.