I'm a commuter, and I actually have ONE (and only one!) toe cage, on my right pedal. That is because I'm a right-footed stopper. In town I stop & start frequently and having the right toe cage lets me pull my pedal up into start position quickly.

Having a left cage was just annoying because I was always fumbling to get my foot back into it. It was easier to just omit the left cage.

I like the toe cage over SPD because I can wear whatever shoe I was going to wear to work.

That said, I have never actually tried SPD. If I ever do get a road bike, I think I would like to have SPD and the shoes. I wouldn't use that for commuting. I wouldn't use it for mountain biking either--if I ever were to get a mountain bike.

My ideal bike fleet consists of my commuter, a winter commuter, a road bike, a mountain bike, a folding bike, and a bent.

My actual 'fleet' consists of my commuter, which I also use for recreational rides.