By combining technologies, Veil offers full time privacy and also anonymity. The hybrid POS/POW system makes the project decentralized, secure and in my oppinion both solid and flexible.

Veil project combines Zerocoin and RingCT technologies, delivering “uncompromising, always-on privacy”.
They use a combined Proof-of-Work and Proof-of-Stake, in order to combine security and distribution. And Veil is the first coin that allows its holders to stake anonymously, generating passive income. On top of this, you can choose the level of privacy you want on your wallet/transactions…
Besides, with support for the Dandelion protocol makes it nearly impossible to trace a transaction back to its source node on the network.
In my oppinion, this one is part of the new generation of privacy coins

Why the mainstream private coins are not my favourites?
On Zcash, only 10% of the transactions are actually private because it is not private by default, nevertheless Zerocoin protocol, provides superior anonymity.
Monero is full-time private, but RingCT, however, based on sophisticated mixing, has been surpassed in terms of strength of anonymity by advanced cryptographic methods. Monero blockchain is also terribly heavy, facing scalibility problems.
With Dash you need to trust your privacy to the masternodes that mix the transactions, there is not much more to say…

A true private coin needs to be scalable, easy to use and as anonymous as a dollar bill