Every so often a game comes along and you have zero hopes that it will be good, case in point - Guitar Hero on the DS. I had no interest in it at all, how could they pull that off?
After looking at the previews for my wife I was interested - and after waiting in line a Future Shop (eh) we both got a copy and I have to say it's a pretty impressive translation.
Of course there are limitations, no WiFi

[<<<< frowny face] and only 25 tunes that did take a hit on the sound obviously. There are lots more of 'right' things happening.
The additional hardware pulls it off, using the GBA slot for a mini-fretboard is pretty slick, pretty small, but slick. All features of the hardware are used - mic, touch screen, GBA slot...as a matter of fact the onlyu thing not in use would be sleep mode for some function....maybe a power nap in between sets could have been employed. :P All DS features are well used. Impressive.
Gameplay - translated very very well onto the little handheld - pretty impressed - it looks and plays just like GH3 for Wii pretty much. Strumming the touch screen and fretting becomes second nature, the difficulty doesn't ramp so lopsided as with GH3, hard and expert are where it's at though. The gameplay comes through in spades.
Sound. Well - it's not lossless for sure - but considering they crammed 25 songs onto a DS cart - it's pretty good. For playing on the DS and for what it is the sound works well, headphones may make it louder, they won't make it sound better. The set lists are nothing to write home about, a few tunes from GH3 migrated over - Black Magic Woman...why?!?!? and La Grange to mention a couple.
Graphics. Might I say it looks the same as the Wii version kinda? Yes I can.....and that's not good for the DS...it's more bad for the Wii version of 3. So in that respect they look pretty good, of course you'll be focused on those little notes coming down.
Overall this is a must have for any DS owner that likes GH or even wants to try it out - such nice effects like blowing into the mic to put a fire out on your guitar or signing a t-shirt make great use of the system, no doubt that little machine is working it's butt off to pull everything off - I don't think they could have crammed much more into it. For a portable version...this nails it to the wall.
Highly recommended. The cons are far outweighed by the pros.