I've owned a TST system for a few years now. I take 3-5 trips a year, usually less than 3 hours one way. My trailer is 31 feet, truck + trailer is 49 feet. I have no issues with distance.
I like having mine. I have the four sensors on the trailer, and two on the rear axle of my truck. The display cycles each tire sequentially about every five seconds I guess. While the system cycles the display, it is constantly monitoring all sensors. If there is a problem (high /low pressure, high temp), it will jump to that sensor immediately and sound the alarm. I can't remember for sure, but I believe the owners manual for the TST says this. Im not near my book so I can't confirm this at this time.
It doesn't take but a second to look at a pressure and temp, then back to the road. You don't sit there and watch it. Many of us spend longer than that figuring out which lane you need to be in for that interstate split. If you want to watch it 24/7, have your passenger monitor.
I have had three tire failures while using the TPM. I can say now I know the problem is I was sold tires that are not rated for my weight. When brand new, they were fine. After a few years, not so much. Two times, I was warned of decreasing pressure and able to get off the road before the tire or camper were damaged. Now the blowout, no warning but that alarm went off and alerted to 0 pressure and a quick check in the mirror told me I was in some deep doo doo. While there was some damage to the camper, it was mostly cosmetic.
Thats my experience. Hope it help you decide.