Load Script flexibility and power. In-Memory database where you can load the tables as you want - not forced to have a specific data model type in mind. The speed of the completely in-memory database as Tableau even with its attempts to emulate it doesn't even come close (Extracts). Documentation when you run into problems with Tableau on how to improve performance is totally lacking. Multi-processor, multi-core performance is hard to understand and to achieve the full benefit of even when Tableau experts try to help you out in specific cases. To me this seems a whole lot less mature than QlikView. 64-bit support is less than three years old in Tableau I think.
Support from Tableau is abysmal when it comes to performance and optimization issues as well.
QlikView on the contrary is quite well documented and support is superb. Tableau Extracts which should do in-memory high-speed queries without touching the database is not working as well or not even close to QlikView's native in-memory. There are lots of problems relating to them. So some customers of Tableau seems to throw in an IBM Netezza to solve their native lack of high performance in-memory db.
On the Administrator side Tableau needs often in even a basic setup many minutes ... like 7-15 minutes to restart servers so a configuration with fail-over, clusters and so-forth that might take a few hours to set up with QlikView takes you not less than two whole days with Tableau - that is if you are really lucky and have a long experience....
I speak from experience having saved a major bank in Norway - their insurance department analytics team after their upgrade went bust. I had to personally patch Tableau 8.3 without any help whatsoever from Tableau in Ireland nor in the US. We contacted them after a couple of hours and kept them informed every day for a whole week. Although they acknowledged the problem and I gave them my patch that it took me two days to make as a beta and three more days to finalize... Tableau support paid me just lip-service the entire week.
When I run into problems with QlikView installations I can send an mail to QlikView support and they always call me back within the hour and there is always an experienced expert up for remote control and to fix the problems.
QlikView has a scalability lab in Lund in Sweden that often are more than willing to help out with performance problems for larger accounts. To my knowledge Tableau does not have anything of the sort.
