Some people like to start their morning with running because it makes them feel energized for the rest of the day, giving their body a healthy dose of oxygen. Just for the record, in that way, the metabolism is pushed to burn more calories.
Others rely on the post-work effort to wind down from their email-meeting-email-repeat workday. When running in the evening, you may feel relaxed and satisfied ending your day with a hard run. It is interesting to add that there are also people who adore switching the time once in a while. In that way, they can benefit from all the advantages running has to offer.
While the best time of day to go running is whenever you have time and can be consistent with it, and what works for you, the bottom line is that some exercise is better than none at all. No matter when you prefer running, it's best when you choose a place where you can relax and be at ease, where the scenery will hold your attention and take your mind away from what your body is up to.