I cant believe the last "review". I've never read something so wrong in my life. I can only assume they are a Nintendo or 360 fanboy.
Singstar never pretends to be a Kareoke machine. I've owned all the previous incarnations of Singstar on the PS2 and they have all been great fun to play. Its very popular at various parties i've been to and everyone loves to have a go.
Play for 15 mins of fun? Maybe if you are playing it by yourself.
Yes, of course you could buy a proper Kareoke machine but thats not the point (and i dont know of any Kareoke machines that can play Blu ray discs either)
There are around 30 songs on the disc and you can get more online. "Oh, but they cost 99p each" scream the moaners. Big deal, i spent more than that on a cup of tea and a newspaper on my way to work.
Ignore the bad reviews and the Sony haters. Get this game in time for christmas and you and your friends will have the time of your life.