Haven't tried OrangeTheory myself -- but there's one right around the corner from me, and I have many friends that swear by it. Definitely find the structured workouts to be compelling -- and HIIT strategies have definitely worked for me.
Haven't gone to a strength-based fitness class in a while though. Typically, the only classes I end up going to are yoga classes -- then the rest of my training revolves around running/cycling outside (or inside), and some time at the climbing gym.
Thanks for sharing! Great post! We've resteemed this to the front-page of EXHAUST! Looking forward to more!