I have both an MXT and and XL Pro. They are VERY different machines. Both are great coin and jewelry detectors. They setup differently. They sound different. When set up for maximum sensitivity, they seem to have very similar depth when using the same size coil. The XL Pro hits slightly harder on quarters and silver items. The MXT hits slightly harder on nickels and small items, and it hits very hard on small foil. Both have a wide range of available search coils but the MXT has the most.
The XL Pro takes a bit longer to setup to hunt ... setting the Signal Balance to max sensitivity is very important. The XL Pro has a longer learning curve and more options for hunting modes depending upon hunting conditions. The analog meter and the audio give a lot of subtle indications about likely target identity ... that is part of the learning curve.
The MXT is almost a turn on and go powerhouse. It has a very short learning curve after you become accustomed to the chatty threshold. However, you will continue to learn things about it for years. It is a very forgiving machine meaning it handles a wide range of soil conditions and sweep speeds. Headphones with a limiter circuit are almost a necessity.
Your preference may come down to whether you prefer an analog meter and subtle audio or a digital display and chatty powerful audio. Or, you could be like me and thoroughly enjoy them both.
From post I have read, both machines are highly regarded by many in the relic hunting community. If you plan any nugget hunting, the MXT is the clear winner.
Hopefully Monte will chime in and give a clearer comparison.
Bob