RCX5 found it surprisingly light and small. It doesn't look like a computer on your wrist like many other GPS watches. Of course that is largely because the bulk of the GPS components and battery are in an arm band.
The armband and separate GPS device seemed like, and became, one extra piece of equipment to worry about.
The watch, heart rate monitor and foot pod all use watch batteries. Battery removal can be difficult, however once the back is removed the batteries are easy to install and replace. The GPS piece is charged with a standard USB cable.
The speed and cadence sensors batteries are not replaceable. These sensors must be purchased again when they wear out
The speed and cadence sensors are attached to a bike with zip ties. I found them easier to install than the Garmin sensor largely because they are separate devices. It was easier to position each of them so that they picked up the magnet from the wheel/pedal separately, rather than trying to align one device to detect both.
Additionally the speed and cadence sensor each have a built in led light that flashes each pass of the magnet.
However, to configure your stride length is tricky at best. The best way to do it is to run a distance using the stride sensor that you know the actual distance of, then change the distance in the history. So let's say you ran 1 mile. The watch believes you ran 1.1 miles. By changing the history to 1 it should adjust the settings so that the next mile you run will record correctly.
Once you have been using the watch for some time you can get into advanced setup. You can add your own sports, or configure the devices, and screens setup with each sport.
You can do this from the watch, but it is easier to do it from the Polar Web Sync software. The software works much like a remote terminal for the watch. You connect to the watch and add or change each sport profile, or change user or device settings.