a uth pad is definately better if your using just one aquarium.
technically u could use the same thermostats, if you hook up the heat tape or uth to a power bar, as well as the heat tape from a rubbermaid rack.
however, depending where your probe is. it will either heat the rack properly and supply the same amount of energy to the aquarium (which might not be the correct temp) or vice versa.
you could obviously try it and see. but i would think different temps would arise between heat tape and plastic and heat tape/uth and glass.
Many ppl say heat tape is a fire hazard, but really anything electrical is a fire hazard.
Especially those tall house lamps from ikea