I don't know if FA's are THAT fun, but they are fun. I've had the pleasure of shooting a few...
Full size UZI
There's a place in Ogden that rents all kinds of FA's, but some that I've got to shoot were property of the local PD, and I know a couple officers that shoot a lot. By far, I'd say the P90 was the most "Sh*t Eating Grin-ifying", but don't tell my wife. hehehe