Never had a grease fire in my smoker and anyone who says they sit by their pit for 16 hours while butts are cooking is FOS.
I have a guru DigiQ and I love it for overnight cooks. I use it on my 22.5 WSM when I smoke butts or whole hams. Temp holds at 235 all night. I just purchased a LBGE last month and it seems to hold temps very well but if I do an overnight cook in it I will use the DigiQ on it as well.