The only people who really need Polyscience circulators are restaurants and food service professionals. The advantage of the Polyscience circulator over the $200-$300 alternatives (or the $100-150 Auber DIY setups, or the $50-75 full DIY setups) is mostly volume. If you need to queue up 100 servings of protein every day, the cheap setup isn't going to cut it, and also poses HACCP issues.
I use an Auber PID [1] with a crockpot. I "vacuum" seal by submerging food in ziploc baggies in a sink full of water. It all works fine, I've never felt like I needed to drop hundreds of dollars on fancy equipment.
