Got the Detech Ultimate 9" for the Apex. I tried to do an air test comparison with the stock Viper but EMI is a huge issue in my house and yielded similar range with maybe 1/2" better on the Detech. I took the machine for a quick run over at a local school yard that buddy and I hit quite a bit over the years. The school has a trash line at 8-10" of cans, tons of can slaw and ground balance runs in the low to mid 90's from the rich black soil. I only made one pass up the field and back and am pretty impressed with the performance of the machine.

In the field it is definately deeper but will compare with my buddy on targets next time were out hunting together.
So my impressions, the coil is pretty much the same weight as the stock, looks really nice on the machine. Pinpointing is better, id's are more stable. Separation seems a little less than the Viper but being less chatty I will keep this coil on.
I noticed the cans that usually ring in at the low to mid 80's are now lower in the 70's (zinc penny range). All other numbers for coins are the same just the trash seems to be easier to identify.

As you can see in the picture my trash to treasure isn't bad and was able to easily pick out nickels we missed over the years from the slaw.

Lastly is the price tag worth it for the machine? $170 shipped is a bit steep especially for a machine in this class so really if you use your Apex a lot you may like it more but also consider a Ripper coil too and really debate which will serve you better for your hunting. For myself I plan to use it for woods hunting and find round coils are easier to nudge small twigs and junk out of the way but that is just my hunting preference.