The actual shifting process became an almost entirely solved problem when hyperglide was introduced thirty years ago. Even Tourney-level parts can shift pretty much perfectly when they're in good repair and properly-adjusted.
The biggest hitches to this have been things like when Shimano switched from "non aero" shift routing to under-the-tape, and took a generational cycle to work out the issues with the new design.

Assuming everything is compatible and well-adjusted, the question mostly becomes an issue of preferred shifter ergonomics.