Not sure what webos is like on phones, I suspect android is better there, but webos is a better tablet os than android and iOS. It takes advantage of the extra screen space where android assumes it has to conserve every last bit.
By "better" I mean more elegant and pleasant to use.
Also, it looks as though webos will be far more open than android currently is. We'll see if google responds in kind.
There may not be massive numbers of apps for webos, but it does have quite a lot of functionality once you've got preware installed. X server FTW!