I switched from the Mach analog OEM to a Mach digital, but got tired of having to turn on a light or hunt up a flashlight to see settings a night. So I swapped again to a battery operated Honeywell which has a back light that turns on when you push any of the buttons. Its been installed for a year and we have yet to have to change batteries. The Honeywell doesn't handle two speed fans, but you can install your own switch. I found a black rocker switch that I put below the thermostat
Link to the Love Your RV page that I found showing me how to do it.