What I don't like about monero, and why I think it'll ultimately lose to another anon product, is that the transaction history is written to the blockchain, albeit in obfuscated form. But there is no proof on the bounds of what a sophisticated blockchain analysis can uncover given enough information. Roughly speaking, its conceivable that given enough transaction information downstream from a transaction of interest might reveal a "most likely" pairing of an address with a transaction. Or perhaps a global analysis of the monero blockchain along with traditional blockchain analysis could reveal a most likely pairing of all transactions with addresses. The point is that without such a proof I'm not sure how much people will trust it compared to a protocol with such a proof (say zcash). Your exposure to future analysis is essentially indefinite.
What I don't like about Zcash is that privacy is optional and address balances are public. This means that a blockchain analysis company could correlate what is public (all the other transactions and all the address balances) to deduce who the sender, receiver, and amounts were in private transactions.
What you said is essentially meaningless though. "I don't like a blockchain-based currency because the record of transactions is permanent." Well...yeah, that's the whole point of blockchains. The strength in Monero's case is that everything is so obfuscated (and amounts + addresses are encrypted) that it's the best option out there. It doesn't have to be perfect, it just has to be better than its competitors.
e.g. Facebook isn't perfect, but it sure obliterated MySpace.
Not meaningless as the links between sender and receive can be eliminated completely depending on the protocol in place. The record of a transaction has to be on chain, but not necessarily who participated in it, or the nature of their participation.
It's true that a system doesn't have to be perfect to win, but I don't see how monero has the edge on any dimension. It's not necessarily the most secure, its not the furthest along in development, not the most user friendly, not the fastest mover, etc. The overall bullishness people have for monero is because its supposedly better in terms of privacy than its rivals. But this is dubious without the right kinds of proofs when the competition does have proofs.
