I bought Canvas Curse and really, really liked that game. It's probably my favorite DS game that I own, in fact, and still gets popped in from time to time.
On the strength of my liking of Canvas Curse, I bought and really enjoyed Kirby's Adventure on Virtual Console.
I bought Kirby's Dream Land 3 on Virtual Console, but have not, as of yet, started to play it.
I bought Kirby Super Star Ultra on the cheap, and I'm sorry to say that I got really bored with it and sold it to break even. I didn't get very far, and I plan on revisiting it someday, but it really didn't grab me after 3 of the 8 (9?) "minigames".
I think what really hurts the Kirby games in the long run is that:
1. They're all really easy, easy enough that they are supposed to be accessible to young children.
2. They all have very similar structure, so far as if you've played and own one, there's really not an overwhelming reason to need another one unless you really like the series. Apart from Canvas Curse and some new abilities, the core series hasn't evolved much in almost twenty years.