The base shapes Kansai
Kyoto is the automatic Kansai base for many first trips, but Osaka can be smarter when evenings, hotel choice, price or onward transport matter more.
When Osaka works best
Choose Osaka for food energy, spontaneous evenings, easier day trips to Nara and strong rail access toward western Japan or Kansai Airport.
When Kyoto is still better
Choose Kyoto when early temple mornings, traditional atmosphere and slower streets are the main reason for the stay.
Compare real days
Do not compare station-to-station times only. Compare hotel room to first real stop for a Kyoto day, a Nara day and an evening.
Best compromise
Three nights in Kyoto and two in Osaka often gives both atmosphere and evening energy.