Anyone use a Password Vault app?

I've downloaded a like a Password Vault App for my iPhone i'd like to use but got a couple questions.

This app is the one where you have a main master password and once logged in you can use the password generator to make really secure passwords and store all your importnant information. I like it because I can generate truly complex passwords and I have all my important info in one app.

The thing is, I feel vulnerable if I have all this information on my iPhone, if I lose it I'm screwed. There's, for security reasons, no online backup and the only backup is a local one on itunes/my computer (which I think is only accesible if I transfewr to my iPhone, I can't read it from the computer)

So for those of you that do use this, how do you deal with this?

Do you keep another copy somewhere else or write it down or something?

Again, I love that I have all my files there and I can have complex passwords and security questions, but I really don't know what I'd do if I need to login to my bank lets say and my iPhone breaks or is stolen, then I just lost all my passwords for everything.

For exactly that reason, I don't trust password apps. Too many apps get destroyed by update and nobody guarantees the app will work in the far future.
I write it down and hide the asswrd in plain sight in standard text files. This file can easily accessed and backuped in different ways. But each file contains very little info, I even lock out myself that way sometimes. Like I write down only half of the prashw or use mnemonics, initials of a sentence…

I store mine on my computer, not phone where its possible it could be lost. The other thing is I always have a number on the front of all passwords that is never listed, for example art is the first 3 letters of all passwords but its never listed… So even if someone got all my passwords they couldn't get them to work without knowing that art is the first 3 of everyone of them.