Well, I have an Ultra 2 so in my biased opinion the Ultra 2 still offers more than S10:In your opinion is the Ultra 2 a step down from the S10. Part of me says it is beefier but sleek in the new black, especially since Apple finally debuted a metal band for it and I could order it and if I don’t like it return and get the Stainless.
Battery life
Dual GPS
Water resistance (diving)
Brighter screen (3000 vs 2000 nits)
Action button
Flat glass - for me, much easier to read than my S7 but ymmv