heat cable vs. Flexwatt

i build a rack that holds 12qt and 28 qt tubs, 4 12qt and 2 28 qt to a shelf, and im contemplating on either using flexwatt or heat cable?

what should i use?

btw corns and bps will be housed in this

shelfs are 48x18.5"

I have heard lots of bad things about heat cable. I'd stick to tape