V-Bar is a great lounge. We stopped in here for some drinks before having dinner with friends. You really don't know there is a huge casino outside of it...the couches are dark and the room is inviting. Its rather small so I would imagine it would get crowded quickly later in the evening.
Update:
We went back to V-Bar with friends on a recent trip to Vegas. We easily were given a table which are really well laid out. I liked the u-shape as it was very conducive to conversation. Our server was great, she always kept our drinks coming and was very sweet. The music here is great, it's a good mix of but is never too loud so you can carry on a conversation without screaming. (Even though I did lose my voice that weekend I don't think it was because of V-Bar!)
I think V-Bar may be my favorite hotel lounge in Vegas.