Just ordered the 16gb version. I'm not much of an android guy, but for that price and the fact that it's pure android (not manufacturer customized shit) and it's running the newest OS update...meh, why not.
If they want to compete with the iPad, they'll need to get down into the $500-$700 range, but I doubt they'd be giving that kind of price guidance if anything under $400 was remotely possible in Microsoft's own view - their estimate is probably a "best case" outcome given how incredibly fuzzy they were about it. (Arguably they could deliver at $1000 and claim they're still "competitive" with an Ultrabook.)
For less than half the price you get more than half the performance. I don't think theres benchmarks out there yet but I don't think its fair to say that a Tegra 3 Quadcore is 'low-end'. It's on par with the A5& A5X technically.