I've trained before, after, and both before and after work.
Honestly, I am not a "morning person". I feel like absolute shit in the morning, and many times have DRASTICALLY more energy in the evening. That said, I noticed that when I workout in the morning, it can sort of "cure" my bad feelings. Furthermore, when I work out in the evenings, I'm often disappointed as I don't feel the workout goes any better than my morning workouts. Despite having more energy before to begin, the workout isn't really any better.
Hence, I usually try to workout in the morning. However, just motivating myself to fight through the depressing "morning feelings" and get to the gym requires a tremendous amount of energy and generates a lot of stress for me, even the night before. Thus I feel it's sort of a wash... I actually think the ideal time to for me to workout is sort of in the middle of the day. Another conflict with work life, sadly...