I own one of Paul's sweater box racks. I love it, and I am planning to buy more when I get the funds. The shelves are hollow so that you can thread heat tape through it, but keep it from contacting the tub. I'll tell you why I think that a three-slot rack is worth $195:
I own a variety of racks and cages- HerpEnclosures, Vision, Neodesha, Boamaster, and home-made. I have always had difficulty fine-tuning temperatures using thermostats and heat tape. The best thing about PMHerps racks is that you can place the thermostat probe directly on the heated shelf. This prevents the probe being knocked out of position by the animal, and it also prevents the probe from becoming a hot gummy mess from being taped directly on the Flex-Watt. With the thermostat probe taped onto the shelf and a thermometer probe placed inside the tub on the warm end, I can accurately set a basking temp without the risk of it being 'adjusted' by the animal inside.
I'm coming up on seven years of keeping snakes, and this is by far the best rack design that I've used. I've heard that some of the RBI products now come with a built-in slot for your thermostat probe, but I have not used any of them myself. I also like the material better than expanded PVC. It feels smoother, harder, and less like a sandwiched foam board.
Hope this helps. I really think they are worth the money.