3.5 rounded down.
I went to the Bacchanal first, and the Wicked Spoon is no Bacchanal, but still quite good compared to most hotels around town (Did you know the one near the entrance of the Rio is actually quite good?).
They have a decent selection of food - I actually really like their cheese selection and salad bar. There's even a make-your-own-macaroni section, and the dessert gelatos are more eccentric than other places. Also, the service was nice - the waitress was actually friendly, which is rare to encounter at any buffet.
I don't really remember the price tag, but it's cheaper than Bacchanal.