Which do you feel has an overall brighter prospect for the future?
In my opinion it is XMR, from a technical and team point of view.
However, once confidential transactions are implemented on to Bitcoin, it is hard to see purpose for any other privacy coin.
First as your title says we talk about privacy and neglect Trusted setup that is a no go for ZEC. At privacy. ZEC is currently a Bitcoin. 0.3% of transactions are not transparent. If Bitcoin will add privacy features will be like ZEC. It wil never be like Monero.