OK, I'm late to this thread -
I own several coils for my Explorer.
The Joey is my primary general use coil. I've had great luck with the coil - thanks again to James_ND for the info on it, and Rick_ND for selling it to me. I've waterproofed the coil by loading the cable stress relief with silicone, wiping silicon around the stress connection boot, and keeping the coil cover connection to the coil wrapped with electrical tape.
The x8 is by secondary coil. There are some very old parks in Omaha, and when I get down that way and have time on my hands I always hit one of the parks in particular and I've yet NOT to walk away without deep silver and/or wheat's in my pockets.
I own the Excellerator 6" coil and the x12 coil and I've not had the opportunity to swing either yet. I bought both of them over the winter, our frost has just broken and I'm getting very excited to get on both of them. Thank-you Bryce_IL for the advice on the 6", I'm sure it will find a place in most used ranks.
I own the MLEx2-1050 and I'm having some technical difficulty with it presently - thanks a lot for the PM Christopher-Ohio, I got your PM & have responded, I'll take your advice, and I'm 100% positive that things will work out in the end.
And as one would figure I own the Slimline-10 that came with my SE. I've only had instance where it gave me trouble, that was when I was swinging a wet volleyball sandpit, got the coil covered in sand, rinsed it off under a pump and it went totally dead. I remembered the sticky note from Minelab stating to wash out the coil cover and the bottom of the coil - that fixed it.
In close I'm sure you'll be very happy with the x8 - I am. If you can come across a good used Joey you should consider picking it up, it's a pleasure to swing.
Take care and good luck,
Doug M.