I got a couple things to say here about this
Little background; I have tons of handheld consoles (dingoo, caanoo, nds, odroid, palm pre, ipod touch, ipad, multiple netbooks, and soon to be pandora) I also have several android phones, htc hero, htc evo 4g, and a samsung galaxy s (epic 4g variant [the one with the keyboard]) I'm all across the spectrum, I try to come off as un-biased but I do have a particular fondness to android, but for obvious reason as I will state below.
let me just start off and say as far as an interface the multiple functions of a mid android is completely where it's at. It may not be the most efficient when it comes to coding as some people have pointed out previously. But as far as just mutitasking limited real estate touch screen centric environment, the tip of the hat definitely goes to android. I can't say I've used a pandora yet so take my opinion as just that, but please note I have used linux in multiple forms in the past. I just can't imagine that being too useful on such a small screen, especially moving windows around. Android gets rid of those windows and makes everything you run a full screen app and you can switch between them at a push of a button. Litterally.
As far as horsepower, yes there are things alot more powerful than the pandora. But as you can see on things like the psp and the nintendo ds, power does not equal potential. The software is what a device great. Just because you have a strong processor doesn't make your code any more efficient it can make it run faster but more can be done with a talented coder i think when comparing things like the galaxy s phones and the pandoras soc. I'd say by comparing the performance on my pandora era specs (palm pre/motorola droid) to that of the samsung galaxy s, while faster it's not night and day as far as what can be ran on them, things just generally run better on the galaxy s but that's because it's more powerful, but it's not the difference say between a 486 and a pentium, i'd say it's the difference between say 1.6ghz and 2ghz processor, it's just generally faster but not mind blowing.
So all that being said it comes down to software because the hardware at this time with what's out there right now in the game is not that important in my eyes. It's about to get real with the dual core procs I think, but I'll hold my opinion till then. Software titles quality, quanity, and polish. I know I'm going to catch some flames but all this talk about how linux does things better than android, I honestly see no difference in the speeds of emulators from the pandora to any of the other android phones. I know the emulators for the pandora might not be as optimized as possible but the ones for android must be then because with the layer of fat people are wanting to stay away from with android the emulation speed going full on all the emulators. The number of emulators is equal to or greater on android and the number and quality and polish of software titles are also much greater on android as well. Alot of the problems I've heard with putting a normal linux desktop on a nand based handheld I've seen completely worked out already for android. Some of the issues that has arrisen aren't necessarily firmware and driver issues but actual OS problems. Most reviews I've read are saying the OS is in pre-alpha, I don't think they are talking about the drivers for the installed hardware either.
Battery life is moot, I've never stopped myself from using a peice of software due to worrying about making it throughout the day before I got back to a charger. YMMV
What it comes down to and most have a very valid point, gaming on a touch screen sucks, at least a good portion of games you would want to play. The flip of the coin touch screen oriented stuff isn't quite so good with physical controls. Also physical controls is also where I think the pandora is lacking a bit. The linux desktop was designed for a mouse input. While an alternative has been found it is less than ideal. Much like virtual dpad on a touch screen. The gui interface needs to be redesigned to take advantage of the physical controls. A command line driven computer can work with just a keyboard, the pandora should find it's nitch interface that makes the most efficent use of available controls. It's the only device out there like it and it needs an interface that there is nothing out there like it as well. Untill that time is found though, android with it's touch screen/dpad centric navigation would be a better fit.
that's all I got, thanks for reading.