I have the expensive TST 507 device, and I put off spending the money until I had three blowouts (two due to the Michelin recall in 2013 when I got 7 new tires free from Michelin). After the blowouts, I also was constantly worrying about whether my tires were inflated properly. Several times I would pull over on a freeway and look at my tires to make sure there were no bulges, etc. Also, my cousin had a front left tire blowout in his 44' Class A and sideswiped a truck, resulting in $20,000 worth of body damage, and an almost rollover. I figured $600 was cheap peace of mind, so I broke down and spent the money.
Now, I can turn it on at the beginning of a trip and know tires are OK. It also reassures me when i drive on rough pavement and start worrying if it is my tires or the road. I figure that tires are the most important safety thing on my motorhome, so I don't get cheap ones.
However, last fall, I did have my right front tire overheating. It went up to 140 degrees--really scary. However, when I set the sensors up, I followed the guidelines provided by my TST booklet, and it did not scream at me, although it must have been close to it. (Low pressure does cause it to make a horrible noise that is impossible to ignore.) This was coming down a long steep road, and I immediately thought about brakes, but had them checked, and they are fine. (And, no, I was not riding the brakes.)
BUT, I did have that front end alignment, and so far, all is well with no overheating tires. My biggest problem is the changing weather and altitude. I was in the cold at sea level in CA, and am now higher, and it should be getting warmer soon, so I am taking it in for an oil change and will have them check tire pressure and add a bit to one that is a little low. I got six new Michelin XPS RIB tires in Florida last March, so I hope am oK for a while. These tires have sidewall protectors to prevent blowouts from hitting curbs, which is a big thing for me.