The decision between them is more on deployment and management, rather than a security competition. IPSec is still the standard for tunnels between hardware appliances, which gives the best performance. SSL is fast growing as the preferred method for the "road warriors" to remote in...ease of deployment, less IT support costs and time invested.
Although one can claim that a default setup for router to router VPN tunnel could potentially be a more wide open door for a problem, versus a stand alone SSL remote VPN client. Because another PC on the remotes host network, if infested with a worm that can spread across IP ranges...could shoot through that tunnel.