I also had a Explorer XS in the past... I did some side-by-sides on Saturday.. (not nearly enough to make any kinda claims for "dominance") However, I much prefer the F-75 for inland hunting. I admire the technology behind the Explorers, and found it to do a wonderful job at the beach in the wet sand (which the F-75 is not designed to do), but when hunting a home site, I loved the speed, depth, ID ability and separation the 75 gives me. The Explorer is deep too, but has to be worked much slower, which for my personal taste, is frustrating when you know time is limited. There also is no comparison when it comes to balance and weight..clear winner is the F-75.
Both machines are top notch in construction... durability is still sorta unknown since the F-75 is so new, but it seems very well constructed. I love the fact the lower shaft on the 75 is the same as on the old Fisher line. That makes it easy (and cheap) to have future coil/shaft setups on hand without just swapping (future) coils.
hh'n