I advise you not to worry about a PID controller. The controller on the MES isn't the greatest but that's why we use highly accurate thermometers like the Maverick ET-732 or 732--and there are other brands just as good. If and when the controller goes out on my MES I'll just buy a replacement from MB because I don't want to go through the hassle of dealing with wiring an aftermarket controller which might required drilling holes in the back of my MES. I like to keep it easy and simple. I've gotten great results from my MES in its factory configuration using the AMNPS.
Right now, Susie, I suggest you do the same: learn the smoking basics on your MES as it arrives from the factory, but use the AMNPS instead of putting wood chips in the wood chip loader. Learn about cuts of meat and seasonings and rubs and sauces. Learn some basic techniques and build from there. Get some recipes online and buy a couple of smoking books. I guarantee that within a few months you will be amazed by the quality of the Q you'll be putting on the table and you will get raves from it from the lucky people eating your barbecue.