PalmOS also doesn't get enough credit for an amazingly "discoverable" UI. I've used an iPod Touch and an iPhone for over a year, and learning to do things like organizing app folders, deleting apps and how to show play time indicators in iTunes took a ton of frustrating trial and error. I still have no idea how to select text reliably, let alone copy and paste. Most of the time, I have no idea in advance if tapping on something will show more information, move to a different screen or start dialing a number.
On a Palm, every dialog has a help icon that provides detailed explanations. UI widgets are simple, consistently applied and convey exactly one meaning. The menu is always a tap away. PalmOS doesn't look flashy, but it's tasteful.
If you ask me, new devices have become much prettier, gained better battery life and obtained faster CPUs, but we've slid backwards substantially in usability.