Band Hero seems to be aimed at more of the family than guitar hero with a wider range of songs on the disk. Guitar Hero and World Tour tend towards the rock / metal genre and may not be everyones cup of tea, so Band Hero has more maintstream pop songs ranging from the (drippy) Taylor Swift - Love song, through Naive - The Kooks, ABC - The Jacksons - etc.
One of the more interesting features is the party play option which - when running has the console picking a song at random, and, if you like the sound of it, you can grab an instrument or the mic and join in at anytime. (and drop out again too).
Like the Guitar Hero / WTand Rock Band games its very good, following the same format witha wider appeal. My only criticisms are that the calibration system for video and audio lag (for plasma, LCD and CRT TVs) is difficult ro work out compared to Rock Band and Guitar Hero WT. Also if using a four pad drum kit controller (Rock Band) as opposed to the 5 pad GHWT controller - Some of the tracks are also difficult to play right handed drums as it means having to cross your hands to hit the snare on the fast disco beats. It is of course easier if you flip the game settings to left handed and then play as normal (I am right handed). But you cannot change to left handed or back to right once into song selection.
With the 5 pad (World Tour / Band Hero) controller, this shouldnt be as much of a problem as it has two cymbal pads set higher than the 3 drum pads. (check out the drum controller photos on this site if you aren't sure what they look like)