If the MXT is what you've learned, and you like it, you're probably best off getting another one. Better the devil you know than the one you don't. After all these years the MXT is still a competitive product.
Kinda funny to be saying that, since I work for FTP-Fisher these days, but now and then I step out of trademark loyalty to offer what I believe to be good advice to people using other brands.
If you stick with the MXT, I recommend getting the 10 inch elliptical DD searchcoil for it. That's what the software was tuned for (not guessing, I wrote the code). A larger searchcoil might give you a hair more depth on the deepest targets but will leave behind shallower good targets masked by trash targets and ground mineralization.
