have the TireMinder A1A system with 10 transmitters and am very pleased with it. Comes with repeater so no issues with lost signal from towed. Minder has free battery replacement, so I change them every year. Have never had one go dead. I do not have flow through sensors. Went with the cap replacement ones as they do not stick out as far. In 4 years have lost one sensor to a road hazard. Was smashed but there were no marks on rim or vehicle so all I could think of was it caught a rock. Did not leak any air, but quit transmitting. One of the people we travel with has TST 507 system and they are happy with it, so I would say you could go either way and be fine.
