We have had great results with our implementation of Account-Based Forecasting, and our CS leaders and CSMs love the ease of use! Many of our teammates were heavy users of Opportunity-based Forecasting before we migrated to Account-Based Forecasting, and some notable parity gaps between the features have been mentioned often by power users, including:
Post Forecast Notes to Timeline button:

This feature saves several clicks for CSMs to post important updates to Timeline and ensures that Renewal Center updates are not a missed second step after having critical renewal discussions with a client, which drives overall forecast accuracy.
Column Header Search:

Column header search is a fast, temporary filter option that can be applied to the columns visible to the user. This helps users avoid permanent changes to forecast views, allows quick scenario reviews as these filters should still be reflected in the summary ribbon KPIs, and makes forecast calls faster, allowing more risks to be addressed in a given time, improving perceptions of the feature, and driving user engagement.
Details Pane:

Details Pane allows Revenue Optimization Admins to provide additional context from the linked Company, Relationship, or other records, without adding additional columns which may make a view challenging to read. The detail view’s portrait format is better for holding additional long text fields as well. The Scorecard and Timeline tabs keep users in the feature, reducing click-outs and increasing efficiency.
To Gainsight’s Product Team: Are these components on our roadmap? Are there other components that are available in Opportunity Forecasting that we expect to migrate Account-Based Forecasting into, such as the Analyze section?
To the Community: Are there other features from Opp Forecast that you would like to see in Account-Based Forecasting?