Info from a review on the wii version
Pros
* A crisper and more friendly GUI.
* Wide selection of mostly great songs
* Loads of freedom to come and go from the stage as you please
* Backwards-compatible with Guitar Hero World Tour
* High capacity SD support
* Best Nintendo DS cross-implimentation to date
* Utilizes the Wii address book for online play!
Cons
* Minor calibration issues
* Some uneven difficulty issues
* Not all songs transfer from GHWT
Everyone has their own starpower. Wtf? Seriously, they're copying way too much from RB2. Why can't they have their own system. Are they really that lazy?
You Give Love A Bad Name from Bon Jovi was reused *cough*lazy*cough*
Also, RB2 still has a higher metascore + the wii version of the RB2 has a higher score than all of the versions of GH5. Kinda sad.