i seem to be going against the grain for this one....
anyway, review time.
for me, this initially seemed like a cash in on the guitar hero series and from what i saw it was.
Instruments
the first thing you note is that it only comes with 1 guitar which means that they assume that someone else has bought their own guitar with them. first bad point. second bad point about the guitar is that its really uncomfortable to hold. the strum bar is hit and miss most of the time and the unexplained lumps in the yellow and orange buttons are extremely uncomfortable when pressed (it would have been more comfortable if they had been replaced with nails).
the microphone is rubbish, simple as. most of the time it doesn't pick up what you say. i wasn't quiet in anyway when i played this and i was better off when i just started to hum the tone.
the drums are the only decent part you get with it, which makes the £120 price seem just OTT.
Gameplay
oh dear oh dear. it seems when they were given the piece of paper saying "make GH3 rip off" they seem to have taken it to extreme levels.
the guitar and bass are fine, not really any way you can do it different and the singstar top is also fine but why on earth is the drum part a fret bar? didn't they have even a shred of imagination?
it is also alot easier playing guitar/bass on this than GH3, but only when i had given up using the RB guitar and started using the GH3 guitar.
Songs
this is where (for me) it totally disintegrated. when the title is something like "ROCK band" you'd expect 90% of the songs to be rock. wrong. this game had about 8-9 recognizable songs on it with the rest being completely unknown and of pop genre. and there are very little on songs on the disc anyway. it seems like they just wanted cash and made every semi-decent song a DLC.
overall, when you boil this game down, the drums learning curve is through the roof (spent at least 3 hours playing the drums with no improvement) and the singing part is broken (takes low notes as medium notes) so basically what you're left with is GH3 with very limited songs to play.
my advice is just buy GH3. its cheaper and has a larger and better array of songs to play.