I had one stuck to my desks at home and work, and one on the dashboard of my car .... but I've stopped using them.
I have installed the "Delayed Lock" app with it's WiFi plugin. I have it set up to keep the phone unlocked whenever I'm on my work or home wifi (re-locks when you leave the designated wifi), and therefore don't need the dots anymore.
In my car, I'm going to stick the dot on a plastic* cell phone holder and then it will just stay unlocked when I'm in the car with it. (btw, with this phone, it's really handy to use a dashboard-mount phone holder. The handless / always listening controls for sending and receiving text and phone calls, playing music and navigating, are all really great.
I tried using the magnetic fob one day, but I immediately lost it. Several days later found it stuck to a metal object in a bag of miscellaneous stuff I'd cleaned out of my car. I'll probably never use that thing.
*When I first got the phone, I was in a series of meetings for a week and tried to put the dot on my laptop - but they don't work when they're stuck to a metal surface. I re-discovered that today when it wouldn't work right with the holder I have in my car. Turns out it is also metal, but with a foam pad on it. The dot would work sometimes, but really flakey. I'll get a plastic holder.