Device runs with me with LTE Speed Stick I Deutsche Telekom flawlessly since May as a business connection "Call and Surf Comfort via radio". Depending on the LTE tariff the right Access Point Name (APN) must be entered. In "Call and Surf Comfort via radio" tariffs the German Telekom the APN is "internet.home" and not "internet.mobile". The adjustment is made under Modem / Modem Settings.
I use the latest firmware on the LTE stick and currently the firmware 7.0.5 on the router. The router can be updated online.
The wireless signal is very strong, ranging over both floors.
I had so far not a single failure and can therefore recommend this device without hesitation.