All our Vision racks use the heat cable and it appears to work fine. One thing to note though it the tubs do not actually rest directly on the heat cable. With that said you have to understand that it kinda works in a radiant type fashion, so the heat gets spread out a little. Probably about 1/8" to 1/4" gap would be best.

On all the home made racks or display type enclosures we like to use Flex watt type heat tape. It spreads the heat out over a larger area while maintaining direct contact with the bottom of the tub.

Unless you have a router or another device to cut the grooves in the surface for the heat tape or are planning on a back heat configuration I would go with the heat tape. No serious problems with mine yet, but I will say we are slowly switching over to all vision racks which means eventually only the large display racks will have flex watt.