The password safe format is quite close, it is open source, free, and works most everywhere. PasswordGorilla (https://github.com/zdia/gorilla/wiki) provides support for the format on the three major OS'es (Linux, MacOS, Windows) with the same tool, and there are several Android phone apps. that inter-operate with the format, so you could also have your passwords available on your phone as well.
Lastly, the file storage format was designed by Bruce Shiner, so there is some reasonable assurance that the design was done right due to that heritage.
I've used both LastPass and 1Password and while they're not open source or free, I have enjoyed using them both. I currently use 1Password and find it to be a great experience.
I'd genuinely like to know (and I promise that I'm not going for a vi/emacs discussion), why don't more people use KeePass? Specific to asking you, did you know about KeePass and, if you did know, what turned you away from it? It is both open source and free and, from what I've seen, has a good number of clients.
Maybe I'm barking up the wrong tree and the marketing or brand awareness of LastPass and 1Password is much higher than I suspect.
KeePass needs better cross-platform support. The Mono/Winforms experience on Linux is not a good one. Keepass2Android on the other hand is fantastic, and I'd argue a bit better then the original (out of the box support for common cloud services).
What we're really missing is out of the box support for something like BitTorrent sync, so you don't need to centralize your store anywhere else.
I wish there was a de facto standard password manager/data format (open source, free, works everywhere).
As it stands, there are many good ones, and it's hard to choose one, even though any choice is better than no choice.