Our Golds Gym has options for both on all bikes and what a difference in the knee area when you are clipped in. Both of my bikes have the same clips so the shoes work for both.For some reason my knees hurt worse in spin than outdoor riding.
I love my Lake mountain bike shoes because I also do a 25 minute upper body work out prior to class as a warm up. I also love those clips for outside and trail riding as it is easy to walk up to the ice cream stand and order yogert-suger free of course....(okay my nose is growing)