Both good replies with valid points- and I've learnt a thing or two about the remote footswitch function, so thanks to the posters. My baseline for the criticism is the TC Electronics G Major rack unit, which also has a dual engine delay feature, a very nice LED display, plus onboard tuner, not to mention superb reverbs and delays.
However, as pointed out-it also needs a remote midi footsitch for pre-set scrolling, and an impedance matching device to allow connection to the front end of a guitar amp (if you are sans loop)
I assume those who use a triple switch assign it as UP/DOWN/BYPASS and leave the Timefactor back on the amp??