We've been using them since November.
The training provided was woefully inadequate (one hour on the computer). They touted the LEO as being very intuitive. That might be true if you had never used a Tracker, Super Tracker or Power Pad before the LEO. As a group, we still have a hard time remembering which apps have the tasks we want to use. It's like playing a game of Concentration every day.
In terms of ergonomics, they are awkward to use. The small size is nice, but that leads to problems with some of the features like the volume buttons. You are constantly pushing them by accident as you try to push the scan button on that side of the LEO. So it's common for it to mess up your volume (usually to zero) and there is some kind of glitch that happens when you press the scan & volume buttons at the same time. If they were smart they would disable the volume buttons. You can still adjust the volume through a drop down screen like you do with settings on your phone.
We've been experiencing glitches that drop stops and pay codes. You can almost smell the lawsuit that is going to get filed when people aren't getting paid properly due to the problems with the LEO. Another glitch we've seen is a buffering problem when dispatch sends you a message while you are in the middle of a delivery scan. It freezes the screen and you can't finish the POD. You have to close out the app, read the message, and reopen the delivery screen. You may or may not have to rescan the packages and have the customer sign again.
Other that that, they're great! <j/k>