I am currently using the "Tire Guard" show chrome system from Big Bike Parts. I have had the system for about 5 years.
The system is easy to install and setup. The battery life is very good in both the sensors and monitor. I have the small key chain model monitor that I attach to the clutch reservoir with Velcro for easy removal. The monitor is not water resistant. So if it rains, I can easily remove the monitor and store it in one of the glove boxes while still riding.
The system is accurate to within about 1 psi at sea level and about 2psi at elevations over 3000 feet based on manual digital pressure gauge readings.
I had one sensor go bad a few years back while still under warranty. Big Bike Parts replaced the sensor quickly and without any problem.
I do remove the tire sensors and cap off the wheel stem with a standard cap whenever I wash the wheels with a heavy stream of water. I only do this as a precaution. This is not required in the instructions.