Android is the Windows 98 of the mobile world. Everyone's using it and there's a ton of software (apps) for it, but there is a wide range of device quality and the OS isn't all that 'pretty' or user-friendly. Users suffer through without realizing it.
iOS is the OS X of the mobile world - polished and functional.
webOS is the Amiga of the mobile world. It was amazing and advanced in many ways when it first came out and had so much promise, but competitors have largely caught up to the advantages it once had.
I think BlackBerry OS is probably the DOS of the world. It can still keep trucking along for a while, but it's on the way out. I'm not sure what Windows Phone 7 would be...