I understand most of the OP's complaints. I am also not a fan of any one particular brand. I could easily be just as happy with a WP7 or Android phone. The only thing that keeps me tied to my webOS phone (Pixi) is the excellent hardware design. I've said it before, but the Pixi's hardware is damn near perfection IMO. Definitely not everyone's preference, but it is mine.
Anyway, that said... I agree that the lack of a rear camera and having to make two motions instead of one to close apps are non-issues. No tablet has a decent rear camera--most phone cameras are actually better than tablet cameras--and holding a tablet up to take a pic is just silly anyway. Everyone has a phone with a camera, so putting a crappier one on a tablet is pointless. Yes, it's a feature that HP can't include on its spec list, and some people make judgments based on how long the feature list is, but that's silly, IMO. You're not going to use it but once or twice before you decide it's crappy, a hassle to use, and made redundant by your phone's camera, so there's no reason to knock points off for not having it.
As for the closing apps... Gestures are what makes webOS. Yes, there's no X, but that means you don't have to hunt around the screen and look to see where the developer decided to put the X or the "Close" button on the app. Swiping up gets you to multi-task view, then if you want to close it, swipe it away. IMO once you learn the gestures, they become so intuitive that performing them--regardless if it takes one more physical step--is so fast that it doesn't matter. I'm a big, big fan of gestures and use them even in my browser on my PC (Opera). Opera has Xs and whatnot too, just like any other Windows program, but I never use them because the gestures are so much more intuitive, even if they take two motions to make, like down/right for closing a tab.
So in a nutshell, once you "train" yourself on gestures, gestures win every time. Being brand new to webOS, this is not going to be apparent to you, but if you stick with it, I'll bet you will eventually agree.
That said, I will not be buying a TouchPad because of the build quality issues. But I still love my Pixi.