In Ad Hoc Analytics it's possible to use participation metrics.This is something that we often use.In workspace this metric doesn't exist.Its possible to get the same results by creating a segment but having the metric would be easier.

Currently it's not possible to make the following breakdown in ReportBuilder: Mobile devices with the breakdown browsers (metric visits).It is available in SiteCatalyst en Ad hoc analysis. According to ClientCare this isn't a bug.