You know i'm one those weird people that loves out door fitness.
couple good reasons for that
Firstly and most important; i do it because i love it and i think if your doing what you enjoy its so much easier to stick with it long term.
second, i believe you will always get more out of real world training than a gym.
simply as you have something outdoors that you do not have in a gym.... the environment. all those little adjustments your body needs to do to compensate for the environment its moving through means your getting faster results for your time investment