They resemble devcoin more than they resemble primecoin in my opinion. Basically portions of minting does not come from proof-of-work, thus susceptible to abuse (counterfeit) or dependent on the trust of central issuer.
Riecoin sounds much closer to primecoin but we shall see when it’s algorithm is disclosed to public.
What’s the deal with Datacoin? A Primecoin fork? Who made it? Is it legit and does it actually store data? Seems like a good idea. If it is legit, does the amount of coins transacted indicate storage?