However, they still make you specify your carrier (at&t/verizon/sprint). So, you are getting a carrier-flavored version when you buy an iPad in the US and it is only unlocked for travel?
That is terrible. I am vexed.
1) Your iPad, purchased in the US with a carrier selection, comes from the factory with a SIM card in it. This can be used to activate a prepaid data plan _on the device_ right out of the box - via that same carrier's network. (They are minimally provisioned before you get it.)
2) The Sprint/VZW iPads also support CDMA for 3G in addition to LTE (4G) and HSPA+ (GSM 3G). The "ATT" ones do not. (They are different hardware models.)
3) They are all unlocked, GSM-wise.
Not true. Japan has the dubious honor of being the only country with locked iPads. Of Japan country-coded SIMs, they will only work with the single official carrier in the country due to a software lock. They still get to say 'unlocked' though, but the devices only work on overseas networks, not other compatible networks in the same country.
This is after "Facetime over 3G" was promoted (by Apple) as one of the big features of iOS6.
I'm almost willing to switch to a shittier UI/software just to not have to deal with thieving fucks like this.