Here's what I remember about why I chose the system I did:
1. Replaceable batteries in the sensors.
2. If a sensor is not within range, the monitor ignores it - meaning I can switch the sensors between trailers - 2 or 4 wheel trailers. Same with trucks - I could switch between a 4 and 6 wheel truck. When the monitor doesn't detect the missing sensor, it ignores it rather that throwing an alarm.
3. Cordless! No wires to run along the dash, etc. to power the unit up.
4. Small. I can set it in the center console and forget about it - it's not in the way.
5. It will monitor temperature.
There might be more reasons, but I don't recall at the moment.
I found this system (and several others) when I attended the Abq, NM FMCA Rally / Convention back in early 2010. I asked multiple questions about each system and kept going back and forth between all the vendors that had TPMS systems, asking more questions during my "research" on them.