I have used aftermarket coils since the early 90s, but overall I have not been a big fan of aftermarket coils. Why? Because I usually expect the detector manufacturer to provide the best possible coils for their products. With that said, there are three coils that I definitely admire.
I found the NEL Sharpshooter coil, to perform as well or better then many of the other 5 x 9.5 coils by other makers or detector manufacturers. The only exception to selecting that coil, for me, is I like the Nokta 5X9.5 on my Relic as well as that same size coil on my Simplex +. They work really well.
The second coil I have enjoyed is also a NEL offering, and that is a solid, 5" 'Sharp' DD. I currently have that for my Garrett Apex to work the densest brush and debris I encounter.
Those used to be the only two aftermarket coils that got my attention. Today, however oh, there is a third aftermarket coil and that is the NEL Super Fly which I bought brand new to evaluate on a brand-new T2 Plus. Neither have been taken Outdoors, but I set up some indoor comparison tests, use theT2+ at 90 sensitivity, Indian boost process with disc at 10.
The eight or nine brand new detectors I bought and extra coils, I can see the t2 Plus with Superfly has been the first to go when I get an ad up. A very impressive detector with that new coil.
Monte