I have a BGE and use a DigiQ DX2 for overnight cooks. I got along just fine without it but for some reason couldn't sleep very well. I would wake up in a panic several times only to find that the needle hadn't moved 5 degrees either way. Bottom line, if you're like me and need to sleep easy buy one, if you trust it enough to sleep like a baby then spend your money elsewhere. I guess I'm paranoid about wind and temp changes since I live in the midwest where the elements are very unstable. Best of luck on whatever you decide to buy.
FEC120, XL BGE, DigiQ DX2, UDS, Cimarron, Weber Jumbo Joe, Grill Grates, ThermoWorks RT600C