We have the TST but unfortunately, I was in a weak/no signal area for over a week & couldn't get online to see or reply to this or any topics.
I can only tell you of our experience. We have had the 12 sensor TST system for almost 5 years and it has "saved" us several times. The 1st time was to show me a slow leak causing the tire to start going flat from the rubber stem which came from the valve stem hardening and cracking over time as we are fulltimers and our Carriage is never under roof. We replaced our 5th wheel valve stems with metal ones which took care of the issue. The 2nd time we were pulling into a Verizon parking lot and the alarm went off showing high temperature, 165 degrees if I remember correctly. We stopped and took a walk around. When we walked towards the middle 5th wheel drivers side tire we could feel the heat. The tire looked OK so Dutch checked further. I turns out that a brake caliper had stuck causing so much heat it caused the alarm to sound. We would never have known we had a problem until too late. Did we lose the caliper? yes but the alarm sounding potentially saved the rotor, a tire and possible 5th wheel damage.
We had our TST system on our 1996 Dodge for over 2 years & never had a dropped signal. We have always checked our monitor periodically to make sure everything is working as it should. When we bought a 2014, now a 2015 Dodge, I put the monitor in the same place. Our new Dodge came with its own tpms system, which I don't like as well,so we just have 6 sensors now. It didn't take long to see a dropped sensor here and there. A call to TST verified that because of all the electronics in the dash boards of the newer trucks causing interference, the probability of needing a repeater was high. Dutch installed one inside a forward exterior cabinet and we have not had any issues since, so I feel strongly that the dropped signals, which I agree would be nice if they alarmed you, are probably from interference. Another way to check to see if a repeater is needed is to move the monitor away from the dash but to a place where you can still see it. If the signal don't drop, move it back to where you had it and if they start dropping off again, it is letting you know a repeater is probably in your future. I love my TST system and wouldn't be without it. Hugs, Di