I have... but I'm not too fond of storing keys for my webservers on mobile devices which can easily be stolen or lost...
Public / Private key authentication if done properly is more secure
For secure SSH you first need to have a private / public key on the server (I pretty sure ssh-server generate one automatically).
The goal of this key is to to be able to authenticate the server (to be sure you are in fact connected to your server). This private key will / should always stay on the server.
(you probably already have this part set-up)
The second pair or Private / Public key is used in order to authenticate yourself. (so the server can make sure it is you that is trying to log in)
You will usually use the command line tool "ssh-keygen" in order to generate the key. When you generate this key you will be able to encrypt it using a pass-phrase.
It is recommended to always use a pass-phrase. The downside is that you will of course need to enter the pass phrase every time access to the private key is needed (eg to connect to your server).
You then need to tell the ssh server that the key you created should have access. For this you need to copy the public key into ~/.ssh/authorized_keys on your server.
So basically if your Pandora is stolen your key is not directly compromised because it is encrypted
My quick explanation isn't really the best so here is a good article on how to set everything up:
http://www.debuntu.org/ssh-key-based-authentication
It takes a bit of time to get how to set everything up the first time but it really isn't that hard. I guess you're probably really busy with the Pandora, work and all though.