Very tough choice as both are great rides and some of my favorites at both resorts.
I gave the edge to Spider-Man though. It is such a fun and immersive ride that still feels modern and current even after almost 25 years, and is still better than many newer dark rides.
Expedition Everest looks amazing and is very well themed. It is a fun ride, but from an actual coaster ride experience I do find it a bit middling. I still greatly enjoy it but more for the experience as a whole than just as a coaster.