Favorite coils for QED. Small coils... Sadie, 8" Commander.
Medium coils...11" Elite, 14" Elite.
Large coils...18" Elite, 18" Detech, 25" Nuggetfinder, 38" John-hider Smith custom built coil.
I could probably cut this list down to the two most used coils which would be the 8" commander for tight or scrubby areas, and the 25" Nuggetfinder for open country.
The Elite coils are very good, but a little heavy, I guess due to more wire, and tend to be a bit noisier and less stable. The up side is that they are very sensitive and probably have a bit more punch than a bundle wound coil.
I have never had EMI problems with the QED and have found I can get very close to both buried cables and overhead power lines that sent my 7000 crazy.
Ground balance can at times be a bit finicky, but the areas that have given me trouble also caused problems with both my GPZ and GPX. I have actually found that having a manual ground balancing machine can be very handy in some problem areas, being able to eliminate many spurious signals.
Ergonomics.... Now this is where the QED really shines. It is super light and nicely balanced with almost any coil, not requiring a harness or bungy cord for all but the monster coil, for which I do use a bungy cord. You may require a bungy for the larger Elites, depending on your level of strength and fitness, but I do not use one for the 25" Nuggetfinder as it is surprisingly light.
I have been impressed right from the start as to how powerful this super compact detector is. Miniaturization at its best, with a battery life of about 8 hours, and rechargeable, of course.