I’ve done both as well. It has been much more lucrative for me at a gym/club, I can fill my schedule up easily without as many gaps and of course no drive time lost. And like others mentioned the club fills up some gaps in my schedule with new clients too! Alsom, unless you’re doing in home training for a club or you’re in business for yourself already you not only have to figure in cost of gas but liability insurance as well. The exception for me has been mobile group circuit training. I love doing that and if a group of 8 or more pay for a full month of group training it’s worth my time to go to them.
Hope you find the best fit for you!