I was getting these speeds at Sharyland High School.
Ping: 100
Download: 4.03 Mbps
Upload: 0.26 Mbps
In Sharyland Plantation heading south to Military Hwy.
Ping: 104
Download: 13.26 Mbps
Upload: 2.55 Mbps
If your by HEB in Shary Road, you should get 4 bars with LTE signal. Haven't done a speed test though.
They're probably working by your nearest tower. Because of this, it might cause some disruption with the service. (Internet, voice calls, etc.)