[tsac]

the only issue I saw when I checked is the different frequency's are hard to correlate with each carrier. I'm sure Blackberry did not include the statement
"Although FD-LTE coverage is fairly wide-spread across the US, we recommend checking the coverage map of your service provider to ensure the best possible experience." unless it wanted to cover all bases.
Example AT&T covers FDD-LTE 2 and 4. Are those the same as FD-LTE 2 and 4?
HSPA+ on AT&T only covers 850 MHz and 1900 mhz. So getting a direct answer on coverage seems impossible and that may be why Blackberry makes the statement.
Either way you need to be sure it will work in your area on the carrier you want. Remember they only committed to Canada coverage so far.