I have.

Keystone has 3 types of firmware available. One for BTC + DeFi shitcoins, one for BTC + XMR + ZEC, and one for BTC only.

If you want to use privacy coins and also play with the DeFi, you’re shit out of luck, unless you don’t mind spending 10+ minutes flashing a new firmware every time you want to use one or the other.

The hardware itself is secure (audited by the best of the best AFAIK) and has some nice features that the competition lacks, such as the ability to store up to 3 different seeds. This would solve my problem of not having to travel with multiple Trezors IF there was a firmware that supported all crypto I’m interested in, instead of separating it by use case into its own set of firmwares.

The Zcash integration with Zashi still needs some work. Zashi only supports a single transparent address, so you need to reuse it before you can shield your coins, which somewhat nukes your previous privacy. Also, you don’t really know whether you’ve correctly imported your Keystone wallet into Zashi because there is no way to confirm the generated Zashi addresses with Keystone.

Overall, I’m hopeful for the future but I can’t recommend this setup to anyone yet.