whats the best option on windows? install or portable USB key? if using usb key can you make it auto start when you plug it in? say if i wanted to use it on another PC
Multiple clients or one portable one on a USB is much of a muchness. I use different clients of different devices and keep the database shared with
syncthing but you can use dropbox or whatever.
Keeping a portable install on a USB stick is fine as long as it runs on all the platforms you want to run it on. If you want to use it on anything that doesn't have a USB socket (mobile) you'll need to set up some sort of sync anyway so that's why I just went down that road.
I personally have the database set up with a long password (40 character 'diceware' style) and a key file. The idea with a key file (I use a particular photo) is that you manually copy it to each 'authorized' device. This makes it practically impossible for someone to get into your database even if e.g. your sync (dropbox or whatever) gets compromised AND they sniff your password e.g. with a keylogger, they still can't get in because the key file was never exposed. (Unless they get a keylogger onto your system AND are able to read your hard drive in which case you're screwed.)
But it looks like Keepas isn't a cross platform manager so that is straight out the window already.
Looking for something to use on my iPhone, MBP and windows desktop.
keepass is Windows and anything that can run with the Mono library (Linux, OSX, BSD, ...). keepassX is specifically for Linux. For Android there's KeePassDroid. For iOS it looks like there's something called minikeepass. It's a pity there's not something like fdroid for iOS because I don't know if I'd trust anything (especially free) from the iOS store.