Although the WeTab (and some others) look pretty awesome, I don't believe they can beat the iPad for one reason: the App Store. None of these devices will have anywhere near the number of apps. Even if they do run Android, it's a mobile OS 'forced' into a tablet setting. Of course, this could be said about the iPhone OS, but I believe that the subtle changes have made it perfect for a tablet, unlike any Android modifications I've seen so far.
The only reason I'm ranting on about this is because I've been seriously considering getting an iPad when it comes out in Canada (probably still will), but decided to check out the alternatives, but I've come to the realization there are no decent alternatives yet.