Comparing Monero and Zerocoin, here is a post I made in the Anoncoin thread.
Ok, as an example let's consider ring signatures. A solution that provides cryptographically guaranteed anonymity without the risk of keys that can create unlimited coins. Who in their right mind would prefer Zerocoin/Zerocash? Let's use a gas tank in a car as an analogy. Would you prefer a gas tank that has a hole, which has a metal plate welded over it, or one without any hole to begin with? The metal plate should theoretically prevent leaks, but who would choose it over a tank with no hole to begin with?
It seems that your analogy is broken if it is true that Zerocoin can generate the cryptographic accumulator in a trust-less manner using RSA UFOs. I am getting conflicting feedback on whether it is possible or not, but it does seem like to me that they have figured out a way to do it that doesn't require trust:
https://wiki.anoncoin.net/RSA_UFOI am about to do a write up on the remaining anonymous coins I have yet to review, so thank you all for the feedback. I have learned a couple things about Monero, and I do agree that it is probably the best anon solution that is currently in existence (although I need to look into what Darkcoin is doing though as well, because I have heard rumors that they are improving or have recently improved their anon tech. I agree ring signatures > coin join implementations though.)