There is very little difference between VPN SSL connection. Well, VPN means “Virtual Private Network”. It’s an universal notion which designates part of a larger network (e.g. the Internet at large) which is logically isolated from the larger network through non-hardware means (that is what “virtual” means): it’s not that we’re using distinct cables and switches; instead, isolation is performed through use of cryptography….
SSL is a technology which requires a bidirectional transport medium and supplies a guaranteed bidirectional medium. It needs the underlying transport medium to be “largely trustworthy” (when not assaulted, information bytes are transferred in due sequence, with no decrease and no repeat). SSL provides privacy, integrity (active alterations are reliably found), and some authentication (typically server authentication, perhaps reciprocal client-server authentication if using certifications on both sides).

So SSL and VPN aren’t from the exact same amount. A VPN execution needs some cryptography at some point. On the other hand, IPsec must be handled fairly deep within the operating system network code, while a SSL-based VPN just needs some manner to hijack outgoing and incoming traffic; the remainder can be down in user-level applications.

A VPN means that some setup step is needed on the client operating system. It’s rather intrusive. If the client is a customer, having a VPN is configured by him correctly resembles an impossible job. Nevertheless, a VPN means that programs need not be conscious of security, so this makes it much less difficult to incorporate third party software within your program.