dumb
This is a pretty dumb discussion spiraling further into absurdity.
The simple answer is no, the Atrix does not have a 700mhz LTE transceiver.
Lawsuit? Good luck with that.
Complaining about a sales person who did not fully understand the specifications of a phone? Sure, but don't expect anything other than your feedback to be documented and the sales reps in that particular store to be coached on use of correct terminology.
Specific to AT&T if they say "4g = HSPA+/LTE" it does not specify that the phone comes with both, it's saying those are the two technologies that they have or are currently deploying for 4G, any other assumption you choose to make based off of that such as "false advertisement since my phone should have LTE in addition to HSPA+"is just simply that, your erroneous assumption.
There is way too much misinformation in regards to 4G on the internet right now. AT&T had to follow suit with T-Mobile calling HSPA+ 4G due to the industry following business standards (marketing) instead of vice versa. Most people in tune with wireless or savvy enough to read and comprehend facts know that HSPA+ is indeed NOT a 4G technology. Both Sprint's and Verizon's "4G" network, WiMax and LTE respectively in their initial iterations do not meet true industry 4G standards, specifically and most importantly in the speed department.
The FCC and the CTIA as well as any industry expert has always said the requirement of a 4G technology is the capacity to support a theoretical max speed of 100Mbit/s.
NO CARRIER'S CURRENT TECHNOLOGY IS EVEN REMOTELY CLOSE TO THIS STANDARD.
Only when LTE-Advanced is deployed will this be the case and even then, these are theoretical speeds meaning a perfect environment without any form of error-correction or security control. Actual average connection speeds will be significantly lower.
Bottom line is that T-mobile, AT&T and Sprint will all have connectivity in the 4-6Mb/s range where Verizon users will have a slight edge with 7-10Mb/s average speeds in "4G" areas . Buy the device you like the best with the OS you like the best and make sure you have good coverage in the places you frequent, period.