That's going to depend a lot on what industry you're in, what skills your IT organisation has, and what other mobile-enabling capabilities you're interested in.
If you work in a highly regulated industry (Financial Services, Life Sciences) or government (Defence) then probably BlackBerry Dynamics as that's the gold standard for highly secure communications. BlackBerry is not really in the handset business any more - they're focused on securing the enterprise! Note that today Qlik Sense would be accessed via the BlackBerry Access browser, but we're currently working on a BlackBerry Dynamics version of Qlik Sense Mobile.
If you're a smaller, more nimble business that already uses Office365 then I'd consider leveraging Microsoft's Azure AD Application Proxy to securely expose an internal website to external access. This is remarkably easy to install and configure, and supports access using any browser and also Qlik Sense Mobile. It also wouldn't require any changes to your firewalls due to the way it works.
If you're a bit larger, with a capable IT department, and you have broader Mobile integration strategy or want to manage all "End Points" (iOS, Android, Windows, MacOS) in your organisation then consider a leading Enterprise Mobility Management product such as VMware Workspace ONE (formerly "AirWatch") that includes a VPN connectivity component.
Qlik has tested all of the above in our "QlikEMM" lab, and a demonstration can be arranged via your Account Manager if needed.
.png "Former Employee"){kind=icon}
