I am posting from it now and have 3g backup that is very solid, but the 4g service is pretty spotty in thunderstorms it goes out frequently.
The hotspot 4g/3g fallback (sierra wireless) is also a bit weak on the antenna. All in all it is a good backup device but not primary net connection like i am using it for at the moment.
At the moment I am downloading an update at over 430KB/s not bad for a wireless connection
My biggest issues seem to be in the hotspot itself, it loses the gateway and needs a reboot every 24 hours, and sometimes just stops the signal in the middle of the day, each time I saw this before it was really warm so I put a fan on it and it is better. However to get good signal on 4g I have to put it in the window to the west, when the 3pm heat starts beaming down i start having net access issues.
Overall I am pleased and once I have my primary net access in place it will go to being backup and work quite well as it won't be on continually.