I went on both of them last summer. TRON all the way. This is simply the best addition the Magic Kingdom has had in a long time. The theming was 100% worth the long Lightning Lane (it was still Genie+ in my visit) wait.
This is a hard one. As disappointed in Tron as I am, the first 30ish seconds (launch and outdoor part) is more thrilling than all of slinky. Even though slinky is kind of a kids coaster, I find it enjoyable. It’s a fun ride, but not thrilling.
I still haven’t been able to make up my mind. As much as I want to say slinky I feel like if I could only ride one of them while in Disney I’d prefer Tron for the thrill.
I voted for Tron, but it's SO hard to compare. Tron is such a cool concept, and it's such fun but it's SO short. I smile and sing and laugh the entire time I'm on Slinky, so it's possible I actually enjoy my time on Slinky more, if that makes sense.