The answer really depends on whether your clients use Windows or Mac/Linux. For Windows users, a VPN client tends to be easier. For Mac/Linux clients, SSH tunneling is more convenient (though they can certainly use VPN software as well). What client is needed, and the availability for each platform will be a concern. Cisco's VPN client is very popular, and almost universally available, but your router must be compatible with it.
Performance is the big issue with VPNs. Since many folks terminate VPNs on routers, the router must have dedicated hardware for the encryption. Without that, all processing is performed in the relatively small CPUs. It may work fine with a small number of sessions, but not scale. I'm not trying to convince you one way or the other - a small number of sessions may be enough for your application.
On the other hand, SSH terminates on server(s) or even workstations, which tend to have relatively powerful CPUs, and can easily handle dozens of sessions. SSH tends to be more flexible than VPN clients, which has both positive and negative aspects. You can do clever things like use local networked printers while sharing files remotely. That can sometimes be a challenge with some VPN clients. That same flexibility can let a client route traffic that you may not want over your company Internet connection.
There are a number of good books on VPNs
, as well as SSH
. There are many issues to consider if you want to keep your data secure, and it's worth your time to do some reading on the subject.