At present, I've concluded there are only a few 'legit' remaining alt-coins at the moment (ie. not dead yet) , with varying degrees of legitimacy.
Litecoin (LTC)
PPCoin (PPC)
Namecoin (NMC)
Devcoin (DVC)
Terracoin (TRC)
Liquidcoin (LQC)
All of the remaining alt-coins which are not dead are Bitcoin Forks -- with the two main exception being PPcoin (using 'proof of work' along with 'proof of stake') and Liquidcoin (which is based on Tenebrix and modified Bitcoin).
The main advantage of a pure Bitcoin fork (Litecoin, Namecoin, Devcoin, and Terracoin) is that the security model is well analyzed, and the strengths and weaknesses are well-known. Yet we avoid the existing bureaucracy and codebase from Bitcoin, allowing the development to take a different direction from BTC.
However, this 'inheritance' of Bitcoin's security model certainly does not apply to PPcoin.
I have yet to see a comprehensive whitepaper or design document on PPcoin. There is a complete lack of transparency with PPcoin, and it seems to be based upon novelty of 'proof of stake' without any comprehensive cryptographic rationale.
Criticisms of PPcoin:
(1) The author has not published a Design Document or a Protocol Specification ... only an extremely shallow non-academic whitepaper , which prevents analysis of how addition of proof-of-stake affects the security model.
(2) The author is not amenable to community suggestions (such as integrating the proof-of-stake and proof-of-work blocks together, rather than keeping them separate) to increase security.
(3) There have been numerous criticisms regarding the PPcoin protocol security on these forums, but the PPcoin author seems to take a 'trust me I'll fix it in the next release' approach to security. Why rush to release PPcoin in an immature form (with an awful name), rather than taking the time to get the design right from the start? Arrogance and secrecy is not a substitute for security.
(4) It appears the PPcoin algorithm uses SHA256 rather than Scrypt. Why is this fact so buried (in that we need to wade through the source to learn about it?)
(5) Lack of transparency. There is not an open discussion of flaws, strengths, weaknesses and possible attacks. These are shot down by the author as being 'unrealistic' even though these attacks (accumulating 'stake' to attack the protocol) are quite realistic.
(6) The phonetic name "Pee-pee coin"... Would Coca-Cola have succeeded if it was called "PP-cola"?
As such, I do not consider PPcoin to be a secure alternative cryptocurrency. Certainly not until the PPcoin author takes the time to draft and publish a comprehensive and detailed design document and/or protocol specification (with rationale for design choices, strengths, weaknesses, etc) to the community (rather than suggesting the community wade through the source code , and reverse engineer the protocol from the source).
What you say is mostly true. However a cryptographic rationale and novelty seems like a very poor choice of words. You could have made the same accusations against bitcoin long ago. They miss the point. Proof of stake has a powerful economic rationale that is completely independent of cryptography (e.g. it is how most decision-making authority problems are handled in the real world). We have joint-stock companies because this form of organization is very effective. PoS is a very close analogy to a joint stock company.
I prefer a gamble (PPCoin) to something that I am pretty sure will collapse due to many layers of agency problems (everything but PPCoin).
There are a few possible explanations for PPCoin's lack of transparency:
1) PPCoin developers are really awful at English Communication.
2) PPCoin developers are really awful at PR.
3) PPCoin developers are jealous and afraid of being copied/outdone. (open source, but not open interpretation of source)
4) PPCoin developers know something bad and they are hiding it strategically.
I'm hoping it is (1)-(3) and not (4). Who knows?
I also hope that someone will fork PPCoin and adopt transparency, that would be great.
I suggest the fork do
at least the following three things:
1) Stop all PoW generation.
2) Remove centralized checkpoints.
3) Cap interest accumulation at 90 days. [Incentive to keep node running is much too weak right now.]
If it works without PoW and checkpoints, then we will have more valuable real-world data. Right now the use of PoW is just an excuse for including checkpoints as far as I can see. [e.g. the PoW guys can make currency and accumulate a majority of stake and destroy us. It's convenient FUD.] Inclusion of PoW also defeats the point (it is like PoS but also incorporates the implicit fees and waste of PoW).