If you do choose SPD, keep in mind that there are two different styles of cleats.
SH51 single release cleats are designed for aggressive riding and racing.
SH56 multi release cleats are designed for more casual riding and touring. These are easier to unclip.
Sometimes racers and aggressive riders get the SH56 cleats and pull out from the pedals when riding hard and decided that the pedals suck. Sometimes people who tour or ride casually mistakenly get the SH521 cleats, have difficulty unclipping and also decide that the pedals suck. In both cases they simply have the wrong cleats.
I know a guy who does pub crawls and prefers the 56 cleats because he can unclip easier when drunk.
-Tim-