There really isn't a huge difference... but flexwatt is much cheaper so that is what many people use. Plus it can be cut to size as needed.

You set the thermostat to whatever temperature is necessary to get the floor of the tub up to temperature (88-92 degrees) for some setups that means that the thermostat is set to 92 for other setups the thermostat has to be set much higher to achieve the 88-92 degree hot spot. This is why you need a thermometer as well as a thermostat.

Measuring humidity is done the same way as it is in tanks... but the dial type sold in pet stores are junk... I like these, they can be calibrated and have a metal faceplate instead of cardboard (which will warp over time)

http://www.amazon.com/Analog-Cigar-H.../dp/B001RM6U4U