Monero, and all crypto-note infrastructure, is about 2 years behind transparent blockchain technology, and thus has a lot of growth as it becomes a viable option for more use cases.

For example:

Multisignature transactions are just becoming available. The lack of multisignature made it a non-starter for many applications, including on darknet marketplaces, because rudimentary escrow or deposits were needed. When the operator goes down, all your funds are on their server and are gone with it, but with multisignature as seen in bitcoin and ethereum, you always have control of your funds and they are never in limbo.

Meta-assets are not possible yet. Asset creation is one of the big tenants of Ethereum right now, and there are many assets on bitcoin as well for even longer. Many organizations use this as a way to raise capital, bringing in a lot more capital into the base currency's economies. Monero and crypto note doesn't have this capability yet, but being able to issue and hold balances of these privately, with audit capabilities, will be powerful.

2nd layer scaling solutions are not even on the roadmap yet in any crypto note network. Cryptonote has the same scaling problems as bitcoin or ethereum, but the key sizes accelerate that. Cryptonote coins have dynamic block sizes already, but it may react too slow to really help periods of many transactions. Monero already encounters this issue. Bitcoin style cryptocurrencies have Lightning Network via Segwit. Ethereum has Raiden on the roadmap.

Do you have an email I can reach you at? I have a quick question.

(HN hides the email field in your profile, so if you want to make it publicly visible you'll have to put it in your profile's "about" field.)

Zcash has opt-in private transactions which are computationally very expensive. So, they do work, but being opt-in they might as well not exist. In my opinion full privacy must be mandatory for all participants for it to be truly effective. Monero is currently the only project that fits this criteria.

Monero is the -only- option that offers fungible currency. Monero Research Lab is actively employing full time PHD researchers to asses and improve where needed the strength of the underlying crypto and the implementation thereof. Zcash is not an acceptable substitute, as is the common opinion- I mention this only because you say "monero is on of a few options".

Zerocash was developed by (and is still being improved by) full time academics.

Which is probably why they have no idea that the user experience is irreparably broken to ensure privacy.

The same criticisms exist as since Zerocash was just a white paper.

I will say that there is the possibility that they can make the optional opaque transactions the more ready option, but you can look at the blockchain and see that nobody uses those addresses. Zerocash is just a bitcoin clone if you don't use the opaque addresses.

There is ongoing work to speed up private transactions that should make it possible to make privacy the default. At that point Zerocash will essentially be a completely private version of Bitcoin.

And Zerocash wasn't just a white paper, it was peer reviewed and analyzed by security and cryptography experts.

What are the current limitations of private transactions, are they slower than the normal ones?

Not sure what you are trying to say about the papers. I saw they were academic and theoretical.

The current limitations of private transactions are essentially that they are slow and that they don't support things like multisig or timelocks. All of these limitations are being worked on.

The academic paper you refer to had both a theoretical construction and an implemented system.