What did you find out? I'm trying to decide which model to get also LTE in AT&T Los Angeles, specifically if N910U will work.
So I have had it for a couple weeks. At first I was disappointed to learn that I did not have LTE. My download speed seemed low, the icon only showed 4G, and "LTE Discovery" showed LTE, but no band. I spent a couple hours on the phone with AT&T troubleshooting, went to a corporate store to get a new sim, and nothing worked.
HOWEVER, I put my phone into service mode at my house. You enter service mode by entering "*#0011#" into your phone dialer. Once in here, it said that I was connected to LTE band 17. So I went to another city praying that band 4 would be there, because then both LTE bands would be confirmed. Boom band 4 shows up in service mode, too.
So after quite a while of testing, I can confirm LTE connectivity for AT&T on the N910C for both band 17 and 4. I also learned that I was speed testing during prime time hours. So my tower was congested, and that was why the speeds were low. The icon didn't show, because there doesn't seem to be an LTE icon in the system.
On the topic of the N910U, though, I was pretty sure that it was a 3G only device. I may be wrong, and will look into it.
UPDATE: From what I have found, the N910U supports the following bands: 1,2,3,4,5,7,8,28. AT&T uses 4 and 17. So the device only has 1 of 2 LTE bands. So theoretically, you could connect to LTE in a band 4 area, but I also found some reports on XDA of AT&T's towers only handing down HSPA+ even in those areas. You can join that discussion
HERE. Hope this helps.
