ES 450 with T-Mobile

I have an ES450 that I purchased from AT&T. It works OK now. I would like to switch my service to T-Mobile. I have downloaded the ES450 Radio Module Firmware for Generic Operators North America that I can load into the ES450. Is there any experience using the ES450 with T-Mobile? Good idea? Bad idea?

I have no direct experience with it on TMo, but it is certified by Sierra to work with TMo. It should be able to connect to T-Mobile’s Band 2 or 4 LTE, however it will not support T-Mobile’s lower frequency LTE bands (12 or 71).

I have one on T-Mobile. I just updated to the latest generic radio firmware (there is none specific to T-Mobile on the download page). I have consistently low download speeds of .6 Mbps. The upload speed is good at around 25-30 Mbps. It has always been this way for the ES450 on T-Mobile. I suspect a hardware issue somewhere. The RSRP is good and RSRQ/SINR is also good.