Well, I've finished it, which isn't really much of a surprise. Dedede was a pain, even after I tried using any of the powers against him instead of waiting for some star waiting to be sucked up and shot at him. But the two bosses after that were pathetic. That's not to say I didn't die a few times though.
I've come to the conclusion that Crystal Shards is better, for a few reasons; the music seems better; collecting the shards is fun; and overall I guess it's just the charm of CS that I like more. They're both good though.