Kamen Rider W vs Yakon: who would win?

Yakon favored — Slight edge (~55%)

Kamen Rider W · Kamen Rider · Post-Futo Tantei

Tier

HIGH 4-C, up to 4-B

Attack Potency

Large Star Level, up to Solar System Level

Speed

Ftl

Durability

Large Star Level, up to Solar System Level

Yakon · Dragon Ball · Base

Tier

HIGH 4-C

Attack Potency

Large Star Level

Speed

Massively Ftl+

Durability

Large Star Level

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.