I have one, its the latest wilson branded ones.
There are two "Wilson" ones that do 4G. The older one has a switch that sets to lower 700 (at&t) or upper 700 (verizon).
The other one covers both simultaneously.
I have the switchless one, on a verizon phone. I've also thrown my at&t phone in it from time to time.
It is currently installed on a suction cup arm in my cottage window, with the antenna on the metal roof, and when i'm on the road around the region, i'll move it to the truck which has a NMO antenna dedicated to it.
In my cottage, near the window, i have 2-3 bars of 3G. Away from the window it will drop down to 1 or 2 bars of 1X (2g)
If i drop it in the sleek for a few minutes and leave it there, it will eventually lock onto 4GLTE and a few bars.
Primary reason for the poor signal is Verizon has 1 tower in town, its on the mountain, and there is no line of sight to my lot. Plus, the metal roof over wooden roof, and the heavy timber walls of this place block a lot of RF. My department radio (VHF) only receives well if i'm near the window.
The sleek boosts the power well, and the antenna is now high enough that it has line of sight to the tower.
A word on antennas though.
The little 4 incher has a tiny amount of gain in the 880-960 band, and good gain in the other bands.
The taller antenna (both mag and NMO) has - gain in the 1700 mhz band, moderate in most other bands, and really good in the 800 and 1900 bands.
If you use t-mobile, you want to stick with the smaller one, as their 4G is mostly 1700.
Verizon also has some 1700 4G spectrum, but in very limited parts of the country.
Also, if you're installing it in a vehicle, the phantom 3g/4g is a really good match to this system and i highly recommend it. I'm currently running it in my truck, and i've got a second one on a magnetic mount on my roof, i'm just waiting for some coax to run it to the window.