Dynamics 365 Portal Performance

We are planning to upgrade from Dynamics CRM 2013 to Dynamics 365. This may also include migrating from ADX portals to Dynamics 365 portals. Other than migration issues I saw people questioned about portal performance

https://community.dynamics.com/365/f/761/t/271632 

and later Microsoft release notes for October 18 states that they have done something to improve performance

https://docs.microsoft.com/en-us/business-applications-release-notes/october18/service/dynamics365-portal/   

That means there were some issues with performance. Since there is no performance documentation available https://community.dynamics.com/365/f/761/t/271632 

Could people who have recent experience with Dynamics 365 Portal please share their experince about portal performance.