Paul, did you ever use WebOS? I rocked a Pre for a long time. It had a lot of good qualities, but like all tech, it's evolve or die, and first Palm and later HP just couldn't keep up. With that being said, WebOS did the following things better than any competing OS's from Day 1 (or very soon thereafter), and the other OSs still haven't caught up:
Texting/Chat OS integration
Mod/Homebrew capabilities (unintentional, I'm sure)
Profile/settings cloud synchronization (including re-installing previously installed apps automatically, Google is hot on the heels of this)
The system failed at ease-of-use and learning curve, Palm lagged at getting out new devices, and the existing devices had awful hardware, and while the "web language only" development was cool in theory, it made for a great deal of crappily built applications and the inability to produce applications that could actually do anything useful on the device. When I had it, there wasn't even a VNC or RDP client worth installing, and that should be relatively easy.
Either way, I'm sad to see it die, and I hope that some of the other platform developers take lessons from what this system's capabilities.