I get how this can seem confusing. There's a couple of differences between the monitors.
The 2U variant can be adjusted in height and can be pivoted (so it can be turned to portrait mode), and can also turn 30 degrees both ways (so left to right). The 2AE version can only tilt the screen. The only other difference I can find so far is that the 2U variant also has an internal USB hub.
I have read however that the 2U variant comes with a lot of dead pixel problems. Multiple people writing about sending their monitor back to get a second one and the second one also having a dead pixel. The viewing angles might not be great either for the IPS panel that it has (which is supposed to have better viewing angles). Might you want to use the internal USB hub, the USB-B cable you need doesn't seem to be added in the box.