The CD4E had had some improvements since it first went into the Escape/Mariner/Tribute. Biggest problem in the 626 app's was inadequate cooling. Ford made the auxillary transmission cooler standard a number of years ago, and the reliability in later models has actually been pretty good. Clean, cool fluid is the biggest factor in this transmission's durability.
I use any cheap, Ford licensed Mercon V and change it frequently. Since the tranny drain is so easy to access, at every oil change (7000mi or so), I dump 4 quarts (out of 12) that drains, and just do incremental refills. Non-stop NYC commuting is a pretty good test.