The best gyms/workout destinations for travelers

I am an avid health nut and I am looking for a step up from the hotel gyms I'm so often using when I'm traveling. At home, my apartment building has a nice gym but I need a membership of some sort I can use in many locations. Any suggestions/experiences with something like Soul Cycle or a similar program that travels well? Or a gym membership that is reliable? Am usually based in big cities in east/south east