Surface Pro tablets are likely to be priced like Ultrabooks.

As for the 4g Kindle HDs, are they going to be unlocked for overseas use? If you're limited to AT&T in the US and Wifi, that's quite a premium over the Wifi-only SKU.

As for printer support and availability of keyboards, iPad is going to have the most options, since all the third party companies will go where the biggest installed base is.