I have the Iq 110 and use it on my wsm but I also used it on my weber performer with the smokenator with awesome success. My Lil brother uses the guru on his BGE and loves it . I think it depends on what you want to spend and what features you want . I have rock solid results from my Iq. I set it up on the Wsm ,set the temp , monitor everything for about 2 hrs just for my piece of mind then go to bed and so far every time its given perfect results! I would recommend buying a couple extra probes because I have had them go bad at the worst possible time.
Weber Performer,SamAdamsWeber,Smoky Joe,22.5 WSM, Weber Genesis E-310,red thermapen(the fast one)