I used the Inseego M3000 for about six months with a Sustainer SIM card, and finally had to give up on it. It works fine most of the time, but it would reboot itself a couple of times a day, and it was a bit slow indoors at my location because the tower is 1.5 miles away and is blocked by some trees. I mounted the M3000 outdoors to improve speed, but I had to protect it from sun and rain with a makeshift box, and that always made me nervous because the device isn't really designed to be outdoors.
So I asked Calyx to change my membership to Sprout. They sent me a new SIM, and I ordered a WaveForm ProLink. The two work together nicely, and the download speed is about five times faster now. The ProLInk is expensive, but the speed is great and I don't have to worry about the weather now.
The ProLink is directional, so you have to aim it correctly. I knew where the tower near me was, because I could see it when I hiked up the hill behind my house, and it's the only nearby tower on cellmapper.net (I'm in rural Sierra Nevada foothills). I aimed a compass at the tower to get its bearing, then used that bearing to aim the ProLink.
I'll keep the M3000 and use it for travel.