It is not the fastest or the newest, but it is the version where "things just worked." For the independent filmmaker, the game asset modeler, or the studio locked into a legacy pipeline, this version represents the last moment before Maya became a subscription-only, web-connected ecosystem. If you are learning Maya for the first time, start with a newer version. But if you are shipping a film or a game on a tight deadline, 2018.5 is the trusted veteran you call upon.
The answer depends on your workflow.
Autodesk Maya 2018.5 is a specific update release within the Maya 2018 lifecycle, focused primarily on Autodesk Maya 2018.5
: This became the primary viewport, with legacy viewports deprecated to allow for better hardware acceleration and visual fidelity during the creative process. Arnold 5.0 Renderer It is not the fastest or the newest,