Honestly the user interface isn't nearly as hard as I thought it would be. As far as programming a waypoint on your current location, that's like a 10 second to 1 minute job, depending on whether or not you want to cycle through the different available icons, or change the name.
If you're talking about setting waypoints that are not your current location, the easiest way to do it is to set a waypoint on your current location, and then edit the digits of the GPS coords to match what you want. You have to cycle through the 0-9 for any digit you want to change, of course, but it adds another minute to the process, at most. It helps that the buttons are very responsive. There's not much delay between a button press and the screen reacting, at all.
You can also "pan" backwards on your current breadcrumb track, and drop a waypoint along your track.
It's not a full fledged GPS that can do topo and has a color display.. but honestly I like it much more than I thought it would. Easy 48 hour runtime on basic Duracell AA's.
The best way I've learned to use it is to go on google maps satellite view and get the GPS coords of the notable locations I can find ahead of time. Enter them. Then cut it on whenever I'm moving.
Also build quality feels solid, and its super easy to change batteries.