Me, I don't think about them too much. I'm not a huge fan of Karim Rashid, mostly because of the hype-y celebrity design thing. ["Karimanifesto"? I rest my case.] We have and love us some O-Chairs, don't get me wrong, but I'll take a pass on most of his stuff.
That said, these Kozmos Blocks, created in 2003-2004 for the late, lamented artist object company Bozart, are kind of awesome. Bozart created all kinds of artist-designed products that were just sitting there in the museum shop during my kid-free days, and then got turned into instant collectible rarities when the company morphed out of business. [Laurie Simmons' translucent, art-filled doll house and furniture, I'm talking to you.]
Kozmos Blocks appeared right towards the end. Their fanciful Rashidian shapes and painted designs should make them fun, interesting, and inventive toys. Mod*mom says they're pretty fragile, though, and scratch or gnaw easily, which'd be too bad.
If you stumble across Kozmos in some museum shop clearance bin, you're fine. Let the kid play with them. But if you can't wait for design lightning to strike, and so you buy them from the only place I can find that purports to stock them online, they'll set you back at least $160. You might want to keep them on the high shelf.
Lammfromm Concept Store in Japan has Karim Rashid's Kozmos Blocks listed on their site right now for 16,000 yen.