From PAX: Impressions of Guitar Hero: On Tour

One of the best things about PAX was that IGN had set up tables in which you could rent out different games, including handheld games.
The game I HAD to try was the DS's Guitar Hero game. I've read and heard many reviews and impressions and got either "It's good, but not great" or more commonly "It's not that good."

First, I don't think the accessory wasn't that badly designed. It isn't the most ergonomic, as you have to figure out a comfortable position for it, but it didn't give me cramps within my 4 or 5 songs that I played.
Strumming wasn't hard either. If you get out of the rhythm of strumming, problems will occur (ie: it only registers horizontal strums on the touch screen, too far diagonal will stop the strumming).
What was the main problem for me was the rather limited list of songs. Going from Guiltar Hero 3, which has 50-some songs, to On Tour, which had only a handful unlocked on the copy I had, felt limiting. However, in checking the Wikipedia entry, it has a total of 31 songs, quite a bit better then what they had there.
More over, it did feel like the "Guitar Hero simulator" that everyone says, rather then being the "guitar simulator" that console Guitar Hero games are. Which brings an early Futurama joke, of a baseball simulator, then a "baseball simulator" simulator.
Is it worth the $50 msrp? Probably not. Maybe $40, but I think the limited song list took this down for that high of a price point.