The OS was nice; the hardware SUCKED
Heck, I bought my N800 to get away from the crap Palm hardware, like the screen digitizer that couldn't be calibrated (TX, TX, TX), the WiFi that would cause it to reboot every time I tried to use it (TX), the backlight that died (m505), the case that came unglued (Vx), the unreadable screen (m500), the 2 hour battery life (TX), the different-for-every-model chargers and sync cradles, and the instantly orphaned and unavailable styli and hard cases.
It got so bad over here in the US that the big-box stores like Best Buy, who would sell you your own grandmother to make a buck, got tired of the constant inventory change, problems, returns, and unhappy customers and stopped selling Palm products.
But I put up with a lot of that because the OS was very usable. They were the only people other than Apple to actually put "fewest clicks" into practice. Plus it was fast and responsive for the puny CPU they had. I'm writing my own apps for the N800 and really realizing what a challenge that is.