Ya I know, I wrote that post. As I said, although they own the licenses, it doesn't mean that they've deployed the LTE in any of those markets. If you're in one of those markets, you should definitely try connecting.
The latency seems to be much lower on PTA over Phone on HSPA.I was recently switched from a regular data plan (that allowed me to use apn: phone) to a Galaxy S3 4G LTE data plan. Now that I switched to apnta, i can honestly say there is not a big difference. I am still in process of testing, but it seems like the phone apn may be working better for me still, im alternating between the 2.. I think the 'APN Type' field is very important, trying to mix and match variables to see what works and what doesn't.
So you don't ask me for every city, here is the list of metros where AT&T has AWS holdings: