Pull-- I started with an Etrac, then started swinging the etrac and the ctx, then started swinging the etrac, ctx and nox 800.
It really won't be too difficult for you to transition over. You'll probably be really happy at how much more information you get over the nox. Not sure what kind of hunting you'll be doing-- put on trashy park or AndyS and start playing. If you have both machines, cover a yard first with one, then last with the other; then, on another yard, vice versa. Compare signals with both. See what you do best with. It isn't a secret here that I haven't been too happy with my Nox.
I think all of us are always looking for the Skittle crapping unicorn that will lead us to that pot of gold over the rainbow. Personally, I should have just stuck with the etrac-- there wasn't any advantage to me buying 2 more machines.
Pretty much all you have to do is dig anything 12 40 and above. Also, I'm starting to think that conventional wisdom is wrong-- that a tight and narrow program is better than a wide open one. I'm going to apply Elmy's 1-10 program to my ctx and take it for a spin-- it really works for the etrac if you are hunting silver. I'm going to start with a 1-0, then put the '1' in where the zincs hit on ground coin.