Its one of those questions that is so difficult to answer as it has so many variables,ie what size of coils do people use,what size of target and of course ground conditions,you could get someone who uses the larger of the 3 coils that the Deus has and be using it for say Relic hunting,as a result of the target being bigger then of course it stands to reason that detectorist is going to get the deepest target/s,but someone with say a 9'' coil in a park wont hit as deep.
As we are all aware no one detector does it all,the Deus is a very good all round detector,and you use the best coil that suits your location and the targets that you are basically after,this is why i have in my detector arsenal coil from 4'' right upto a 36'' square coil on my Pulse and also a 2 Box setup,someone else mentioned it last night its best to get a set of golf club and then you will be able to play most shots.
I rarely use the controller on a Deus simply because i use it mainly as a audio detector,below a certain depth which is about the 7-8'' range then the VDI No's are a total waste of time,so my way of thinking is why use the controller if the audio is so much more reliable,so hence this is why i mainly use it just for fine tuning the Deus,quality headphones as in WS5 and audio are the key to using this machine especially when hunting say deep roman and saxon coins as you listen to those ultra feint signals that will never even be seen on the screen.
Of course this is just my opinion and how i use my Deus,other will use it differently.