We are basing pricing structure off of Apple products like the iPad, because it is currently the best tablet device available. As such, if the price of these upcoming Honeycomb tabs are more than an iPad, then it decreases the appeal for them.
I would prefer a Xoom over the iPad but not at $800, although I've already mentioned that it is somewhat of a reasonable price for the device. If they released a $500 model of the tablet, then there's no doubt in my mind that I'd choose the Moto Xoom.
Also, let's not forget that the Apple iPad 2 will probably be released soon with similar specs to the upcoming HC tabs. There's a good chance that they'll release simultaneous WiFi only + 3G models at the same price of current gen ones.