I've been there a few times and it's okay, certainly not the best churrascaria I've had. I found the variety of meat a bit lacking
I went there in March and got some discount tix from the Tix 4 Tonight kiosk @ Fashion Show Mall (the one downstairs/street-level). I believe the vouchers were about $3, and it knocked about $15-16 off the meal price.
It's not bad. Be sure to save your appetite for the meat which is the expensive part of the meal. If you go to a show at the V theater at the Miracle Mile you can get a discount for some of the nearby restaurants which includes Pampas. The only people who should not go are those used to a Fogo quality churascarria who will find that Pampas is not quite as good.