Hi littletwig,
I use a BigFoot on my MXT for open play fields and saltwater beaches in Southern California. I have been told that targets sound the same the full length of the BigFoot when used on a DFX. However, targets sound different under the front verses the rear half of the coil when used on an MXT. With just a little practice you will soon recognize both sounds as a good target.
You can cover a lot of area more quickly with a BigFoot. To my recollection, the deepest good target that gave a proper VDI was a quarter at about 6 inches. That was in dry sand. You certainly will loose depth compared to the standard 950 coil. However, for recent coin and jewelry losses, it is a great coil.
Pinpointing is a dream. Tilt up the back of the coil and pinpoint with the front tip. I know it sounds awkward but it is actually very easy and accurate.
Some say an MXT does not handle wet saltwater sand very well. In my experience, that is often true when using the standard 950 coil. With the BigFoot mounted, I do not find wet sand to be an overwhelming problem. I do a ground balance when I go from dry to wet sand and flip the switch to lock. I seldom have to use the Salt position to balance and seldom have to reduce Sensitivity below the preset position. When there is a LOT of black sand, reduced sensitivity and the Salt ground balancing becomes necessary. However, I can hunt under severe conditions with the BigFoot where there would be no way with the standard 950 coil. The MXT will false when a wave washes over the BigFoot. I have not been successful hunting in saltwater with the BigFoot submerged. When I move back to the dry sand, I do a ground balance and again flip the switch to lock.
HH Bob