From my experience, spinning gives you a harder workout because the instructor keeps pushing. As a solo bike rider, the class environment was different and I still chat with the folks from that class when we bump into each other at the rec center. But their goals never quite matched mine . . . I'll probably always be a solo rider.

I'm now at home on a trainer and prefer it over the class. I can ride on my own schedule, putting more time on the bike than the class offered, and there is no substitute for the fit of my own bike vs. a spin bike.

'Course, we would all rather be outdoors!