It's super, good value for money, a reliable company just like with the 4G/5G routers I work with. I use the device with PlanetSim because it comes out very economical/year and is automatically compatible with all countries and has good reception everywhere, including Italy where I went, as I have installed the Ruhavik app which works excellently and with one button I can also turn off the car. (I have connected a relay to the DOUT on the tracker). It is fully reliable and has good response and refresh rate on the data of where the car is located. It provides more information than an average user needs, but it can also connect with a general OBD Bluetooth adapter in the car to transfer more information from the Can-Bus (I saw the function, but I didn't try it because I wasn't interested)

With a Planet SIM card for 25 euros per year renewal, it works perfectly.
I use the Teltonika Free Server application, I installed it myself and the setup is very simple, following the instructions from the Teltonika website.