the bikes at my university (UC Berkeley) only have the cages (ie., clips).

the bikes at club sport (they charge $100+/mo) have spd on one side and cages on the other.

I think it is a good idea to spin in clipless pedals (e.g,. spd, speed play, etc.) especially if you are using this pedal system on the road. Easier to keep up with the cadence, stand up on the bike, etc.