First off, my SingStar history: I barely have any. I never owned or played any of the PS2 iterations, but I do own the original PS3 SingStar. I played it briefly when I originally purchased it, but my music game tendencies quickly reverted back to Rock Band/RB2. I enjoyed it enough that I purchased 4 songs from the SingStore though (which I lost access to when I bought my slim.... that's really stupid and I need to call in and get that shit migrated one of these days). So, I like it enough to play it once in a blue moon, but I'm not a huge fan by any stretch of the imagination. Even though I had the game for about a week beforehand, I never even put the SingStar Dance disc in until the party.
If you've played any of the PS3 SingStar games, you'll be immediately at home with SS Dance - the menus are identical. Whether thats a good thing or a bad thing is up to you - I found it easy to navigate but occasionally difficult to understand what exactly I was doing. The actual gameplay itself is the same SingStar 2-player singing you're used to, plus two people dancing, each with a Move controller in hand. Because the orb on the Move needs to be in view of the PS Eye, the people singing need to kind of stand off to the sides a bit. My living room is fairly large, but my TV most certainly is not. Essentially, the bigger the area, the better. We were switching out people between every song and while the simple player-changes are pretty easy, you have to recalibrate the Move controllers every time you swap out dancers, which can get kind of annoying and can create a lull in the action. Knowing how the Move works from a technological standpoint, its completely understandable, but annoying nonetheless. Each person has to stand hands at their side, then point at the screen, then hold the Move near their chin. I got the hang of it pretty quickly, but it can be confusing for people who don't play games often (especially after 3-4 beers).
The song selection is pretty good; there were only 3-4 songs that I flat-out didn't recognize and I felt that the choices were well-suited for pretending to be a real dancer and making an ass out of yourself. I'm no dance expert or anything, but the choreography seemed to be pretty close to what is seen in the music videos...... watching two grown men do the marionette-on-a-string sort of moves seen in N'Sync's 'Bye Bye Bye' made me laugh til it literally hurt. The songlist wasn't all that extensive, but I suppose that's where the SingStore comes in. It looks like you'll be able to purchase song upgrades for older tracks in order to add the Dance features (and guitar features for SingStar Guitar).
All in all, I was pleasantly surprised by how much fun I had. Granted, a large part of my enjoyment probably came from the beer and having friends over, but the game itself is pretty solid. There are no huge surprises here and the game is pretty aptly-titled. If all you're looking for is a SingStar game that is pop-heavy and lets you act out the dance moves, then I think you'll be happy with it.
Pros:
-Seemingly-accurate choreography
-Good track list (for what it is - cheesy pop music)
-Move implementation seems pretty good
-Its a workout
Cons
-Seemingly-accurate choreography (I'm not a dancer. This is kind of hard.)
-Recalibration can get annoying if swapping out dancers often
-Still no wireless mics in the US? WTF?
-I don't think there is a way to export video clips out to the XMB videos folder (that's a problem with all the SingStar titles, I assume)
-Videos have to be manually saved after each performance, otherwise they're lost (pretty sure. Same for other SS games too)
-Its a workout (no seriously... everybody was kind of worn out toward the end and a couple even reported tummy trouble - having beer and pizza immediately beforehand probably wasn't the brightest idea)
Also... I kind of can't believe both of my kids slept though all that crap.
If you have any specific questions, feel free to ask!