Great rack. I'm using two of them currently stacked on top of one another and am about to purchase two more to do the exact same thing. They hold heat well...though my top and bottom tubs run a bit cooler than the rest of the rack which is to be expected. I like the tubs they use as well...fairly sleek and slide very well. I'd absolutely recommend the rack, best I've used for the price as long as you don't mind 10-20 mins of assembly. Keep in mind that you need to order the tubs separately, but they are reasonably priced and you can order them in semi-bulk if you're buying more than one rack.
Plus, he gets them to you super quick..I think I had the rack before the tubs arrived.