Cloud

A VPN is generally the lowest cost solution. Minimal hardware is required and users can usually keep their existing devices. A VDI system is usually the most expensive, as there is an extra layer of software required to host a VDI system, most commonly Citrix or VMware.
VDI can and should be one of the tools for securing the corporate environment, but it is certainly not the only one. ... In conclusion, while View and VDI is not a security panacea, it can significantly improve protection against some common exploits and can provide a more secure environment for your Windows desktops

Most office workers today use Windows-based computers for their jobs, whether those are desktop computers at a work location, laptops (which can be used in the office, at home, or on the road), or remote/virtual desktops (either VDI or RDSH) where the user’s Windows desktop runs as a virtual machine in a datacenter somewhere (either on-premises or in the cloud). The question of “VDI versus VPN” really means, “When my users work from home, should I provide a remote virtual desktop they can access from any type of device in their home? (VDI) Or, should I get them a laptop which runs everything locally on it and then have them connect back to the office through the VPN to access their files, apps, etc.(VPN)