I've read some not-so-great reviews on this place, and I must say it has to be based on unfortunate coincidence. The experience is fun, food is delicious... the service can be better but it wasn't horrible. I happened to be with great company, which makes it even better (: My advice to you... do not go here unless you're ready to EAT, otherwise you're not taking full advantage of what the place offers.
We all ordered the all-you-can-eat (of course..., that should really be the only option for anybody). As they walked around with the food, there were only 1 or 2 options that I didn't really care for because it was a bit dry for my tasting or too salty; however, the rest were fantastic! The lamb was my favorite, and I loved how their medium-rare steak was actually medium-rare! Melts right in your mouth (: The side dishes are also key factors: the rice and beans, sweet potato, etc... reminds me of Korean-style dining where the side dishes can be constantly refilled and they certainly add a great variety to dinner.
Overall, I recommend this place. I will be trying more Brazilian steakhouses throughout the city that are perhaps more reasonably priced... but I can't bash on Samba for being a tad on the $$ side because it's located in a casino on the strip. Definitely check this place out as a tourist, or you're conveniently on the strip... just bring an empty stomach ;)