TPMS - I know, again!! Need some buying advice!

I purchased the model 507RV with flow through sensors from TST a couple of years ago. No problems at all, and the system saved my bacon last month when I had a tire going down. The system alerted me to the problem and I was able to pull over to take care of it before the tire was completely flat and started separating which would have caused a lot of damage.
I wouldn't travel without my system now.

Sees to be concerns over flow-through sensors propensity to leak. Once you have a TPMS, you stop accessing the valve stems unless there is a leak, then you know and can get it fixed right away. We've have an EEZTire system on our class A for a year now with excellent results with the non-flow thrus. Agreed that the price has been escalating since we got ours. Usually electronic stuff gets cheaper. Even at the higher price I'd gladly do it again. I'm a firm believer that all RVs should have them. Pretty much all travel in an RV is for a longer period of time than cars. With a car, you pick up a nail and when you come out of the store your tire is flat. With an RV, you drive long enough for the tire to leak down enough to overheat and fail at speed. This is a safety regulation that should become law for RVs as most people don't realize how RV travel makes a blowout more likely than in their car.