I swapped my 4″ Trance for a 5″ Fuel Ex earlier this year. Fuel Ex is slightly lighter in spite of the travel, but then again my trance was the first MY and frames were lightened since. I find the Trek’s front end a bit easier to keep down on climbs (I had of course made the change everyone makes on trances and added 20mm to the front sus compared to the stock fork); having a U-turn Rev 100-130 on the Fuel makes it even better if I can be arsed to wind it down for longer climbs.
Neither felt like they had anything like 4+” of travel at the rear when climbing, just superb compliance and traction.
Both are excellent bikes, and I’d say you can’t go wrong with either, but of course try them. I’ve never ridden a Spesh FS though.
How about what a few folks I know have done. get 2 mates of similar build as you to take all three out on the same day and do a half day ride swapping over every now and then, see which one you all rate