I add my voice to those who are satisfied with the TST system. However, dealing with the Mercedes 3500 steel wheels is quite another problem that must be faced in order to get the TST sensors securely installed. I've had mine for only 2 months, but the fuzzy blanket of easily seeing that the tires are OK whenever the road sounds/feel change is well worth the cost and trouble. Mine are on short high-pressure rubber stems (with brass core), and WheelMaster braided duel extenders secured to the center hub of the wheel simulator. I had RoadMaster install them, with my careful step by step inspection, so hoping that I'll have the batteries finally go before having to worry about pressure. And I bought an 8-tire set, so I have my spare monitored, plus a back-up if any fail.
2015 Prism 2150 LE / Sprinter 3500