Socket makes it easier/cleaner and allows you to replace a relay in the future easily. As for which one to get...either one is fine. My fog lights have been running on some china relay for almost 3 years now with no issues. I have 3x spare bosch ones in my toolbox but they've sat there for 2 years now lol. If you use a socket its pretty easy to replace...plug out-plug in and you're done.