Technically speaking - a very dissapointing product, practically a puffed up NV40 with no technical innovations whatsoever (no unified pixel & vertex shaders, no new AA alghoritms, same HSA scheme, Longhorn baseline support is still ways off, etc...). A cheap cop out by NV.
The transparent AA is a cheap (though a pretty nice) trick and the perfomance is obviously top-line for the time being (with ULTRA contending with R520 when that comes out).
Now obviously, on a tech level, Xenon in the X360 is more of a forward-looking product, but what difference, if any, is there between G70 and NVIDIA's own RSX employed in PS3?