Power BI is a cloud-based BI solution that aims at integrating simple dashboard-style solutions into existing Microsoft service suite whereas QlikView is the most mature dashboard in the market. Moreover, tableau is focused on data insights and hence guides people to discover moments in their data.
Data Capture and Transformation: Power BI is more prepared for the job with a massive range of connectors available when it comes to transforming of data like merging sources, matching records, QlikView is still the boss. For dealing with multiple sources of data, Power BI will eventually need some kind of data warehouse. On the other hand, QlikView is also capable as it has a fast scripting engine that is similar to data warehouses function.
User interface: Power BI has an extremely instinctive interface as any excel user who has used a pivot table can be able to pick this easily. QlikView has a feature-packed and enormously flexible interface. QlikView can create dynamic visuals based on highly complex, parameter-driven, and customized aggregates.
Security and authentication: Both are highly secure. Both will integrate into active directory and can use integrated security to authenticate users. Power BI demands AD security which is said to be no row-level security. While Power BI can use group membership to determine access but does not implement user-level security.
QlikView has its own difficulties with authentication when you want to host your QlikView application on the cloud and authenticate with O365 accounts or other single sign-on services.