I have benefitted from a DigiQII on my 18.5 WSM for the past 3 years and would highly recommend it
. Picked the BBQ Guru over the Stoker for its simplicity, just don't need the web connectivity, logging, or multiple pit control etc for my purposes.
WSM with the DigiQII is pretty much set and forget. I appreciate this fact most for overnight butt/brisket cooks. I went with the 10cfm fan and must say I would not change a thing. The Guru has not let me down once and I have cooked year round for the three years I've had it