I go to Burger Brasserie quite often, because it's very convenient, just inside the Flamingo entrance to Bally's. I'm also able to use my TR points and the coupon they give me with my room.
It's mostly a sports bar, so if you don't like that, you'll need to ignore quite a bit. The service is good, unless it's crowded. Also be aware that they close at 10 pm, I believe, and I walked in at 9:55 and was turned away.
They have a menu that includes a lot more than burgers, but I only buy the burgers. There's a good selection of burger styles, and I am happy with the food, which is why I go back. Although I'm not a gourmet, I would rate the food high, and the service slightly lower, for restaurants in that area.
KGB, Kerry's Gourmet Burgers, inside Harrah's, is similar, but it has a Russian theme (rather than sports bar), so if you like vodka, that might be better.
I went to PBR for the first time a week ago, and didn't like it. The food I got was pedestrian, and the place was very loud. But they do have a mechanical bull, if that's what you're into. I think I would have been happier with the Earl of Sandwich, instead.