Pros: - Logical isolation. You can put instances (and RDS, Redshift) etc. inside logical subnets that are not addressable from the outside world. - VPNs. If you really want extra security, you can wire up VPN so one of your VPC subnets shows up on your corporate subnet.
Cons: - A complete pain to manage with SSH-based tools. Most deployment tools (Ansible, for example) and even lower-level tools like fleetctl don't play well (if at all) with jump boxes. Example - Ansible Tower requires instances that are publicly addressable OR placing a Tower instance inside a VPC (which means we can't use it to manage multiple VPCs) - We have had to write our own workarounds for the above con. - Complexity. There are more concepts to learn about. - Lack of portability. I don't know if all cloud providers (Azure, DO etc.) even support VPCs the same way AWS does. This makes our infrastructure less portable than I'd like