Apparently, it just became available in the San Antonio area.

It's roughly half the cost of Spectrum internet (which currently has a monopoly in my part of town).

Anyone have any experience with it?

No Sir. I had T-Mobile for a while, but after Hurricane Ike service went to crap.  Unless you have amazing cell service I personally wouldn’t venture in that direction.  Good luck

I have it, but I live in the southeast part of the state. For me it runs hit or miss. Meaning, every once in a while I have shitty service. If I call and complain I’m usually told that it is because they are upgrading their towers.
Because I have their paperless billing plus it is paid automatically via credit card, it only costs me 50/ mo..  
Before T-mobile I had one of the bootleg broadband providers. T-mobile is as good as them, with the added benefit of not waking one morning to find that you no longer had internet service. It’s also way cheaper.
T-mobile also doesn’t charge for equipment, and if you don’t like it, you can box up their equipment and send it back, no charge.

We live in a very rural area and it works great for us. Average 90mps

It’s intended for rural people with literally no other option than HughesNet. If you are in a metropolitan area looking for a cheaper alternative, you probably won’t like it.   It is not throttled, but There is limited bandwidth and TMHI is at the very end of the line.  Everything gets priority over TMHI.

If you have ever been in a city with “lawn watering days” due to water conservation, you can feel the water pressure change when you are taking a shower in the morning as your neighbor’s sprinklers turn on and off.  Your speeds will be like this.  It will be great at 2:00 or 3:00 in the morning, but it will be slower than DSL on Friday nights before 11:00 PM or so.

TMHI It works great if:

1.You are in rural area that has service
2.You don’t have many neighbors competing for the bandwidth (think water pressure)

Pro Tip:  If you have TMHI and have great speeds, post your impressive #s here, but DO NOT tell your neighbors (The water pressure thing).

ETA:

Rural Internet Alternative

With my limited research it appears to be a device that connects to the 5G tower nearby. Not sure what that means for reliability.

I just ran speedtest.  Here's what I got:

Ping 49mS
Download:  60.25Mbps
Upload:  1.34Mbps

Now let me tell you, this is all over the map.  Sometimes in the evening I can run it and the numbers are really low.  As in, 2-3Mbps for download speeds.  Then for some reason, it magically goes back up.  Sometimes streaming movies or Amazon it doesn't work all that well.  I get freezing, and stoppages.  If I call and complain, they (some foreigner with a bad accent) tell me they are working on the tower that I use.  I'm pretty sure this it just to get me to hang up and wait.

Someone mentioned this above but basically during peak hours you’re being throttled. Meaning cell users are likely priority.