What's interesting about Dr. Vegas, which does feel like a Las Vegas clone, is the cast. Even when he's in bad projects, Joe Pantoliano always delivers his trademark schtick of being a great wiseass. Seriously, you can't beat someone like Pantoliano who adds a breath of fresh air to anything. Another thing is Tom Sizemore's in the show, which seems like a step back considering he's had success in films. Rob Lowe's a decent actor, but unfortunately his character, is just a little too bland.
While Las Vegas focuses on the security team of a casino, Dr. Vegas is a little more sporadic with only one character representing a certain department. Such as Rob Lowe's character represents medicine, Sizemore's character is security, and Joe Pantoliano is the big boss. Since it's a little more sporadic, it's a little hard to keep track of the characters and where they're going. What NBC's show has going for it, besides familiar guest stars, is it's got a unique visual style. That is, a music video style of film-making in the vein of Ocean's Eleven. It's a show that's about hip Las Vegas.
Dr. Vegas, of which I only viewed the pilot, is still trying to find it's feet (that is, if it ever gets back from "hiatus"). There's only a few characters to follow, but rest assured, the success of a show can guarantee more characters being brought in. But this show feels like a barebones operation that's still trying to get it's feet wet.
All in all, I would recommend Las Vegas to Dr. Vegas because Las Vegas is just a little more fun and perhaps, accurately captures the atmosphere of Sin City itself. However, what Las Vegas needs, is an actor like Joe Pantoliano to really stir things up.