Usability is great. This product will make most feel right at home. I feel like this question should be asked from two points of view:
1. Creator of reports, Data Models, Views etc: Most Advanced users will still rate the usability as very high. Its capabilities are still robust. However when compared to other Enterprise Class products it will not do many of the advanced application queries.
2. End user, Consumer: All end users will feel right at home. Many will be able to create connections to already created data models and other external publicly available sources like twitter, Facebook, World Health order etc... These connections are then in turn very very easily available to publish to SharePoint and Power BI.
It took me a while to understand what I think is Microsoft's strategy. This will handle all but the most of robust needs. Much like many American made cars and my favorite Corvette, Microsoft is fast, has it own break downs from time to time but all of these are really to tolerate when the price is considered and the next one up that can out perform it is three to four times as much money makes this an easy one to still recommend.