Oh I agree with both Joanna and Gloryhound. A tub can be a great quarantine enclosure (that's how I use the ones I have) or "for now" enclosure while you get the final one tweaked in properly.
Tubs have their uses. I just think they aren't the best permanent housing unless you have the insulation and support structure of the rack as well. Even then, I don't like how short rack tubs are.

And I do intend to have vinyl flooring in my display cages to keep cleaning easier as well as to cover the flexwatt so it doesn't have to heat through wood.