The Zoom is supposed to be good although pricey. What about Rim’s Playbook?
"The battle of devices has now become a war of ecosystems, where ecosystems include not only the hardware and software of the device, but developers, applications, ecommerce, advertising, search, social applications, location-based services, unified communications and many other things. Our competitors aren’t taking our market share with devices; they are taking our market share with an entire ecosystem. This means we’re going to have to decide how we either build, catalyse or join an ecosystem." -- Stephen Elop, CEO of Nokia.
The challenge for HP and RIM is going to be building an ecosystem. The iOS ecosystem is well-established, and Android isn't far behind; it lags far behind in the raw number of apps, but it's sufficiently robust that there's an app for most needs, and developers find it worth their time to port apps to it. Whether developers will find the time to bring apps to WebOS or QNX is very much an open question. Ditto Windows CE Pocket PC Windows Mobile Windows Phone 7, which appears to be where Nokia is going.
I can't begin to guess how many competing ecosystems the market will support; Microsoft is a credible third player just because they have tons of money they're willing to lose in the intermediate term to gain market share (see XBox). RIM is trying to leverage a base that's been fading for a couple of years, and Palm HP one that's been fading for five or ten. WebOS could be the OS/2 of mobile operating systems, a solution a lot of folks thought was the best available, but that never really got off the ground.