Well mine are spayed, however Mitzi isnt and the only reason is because she has a heart condition, therefore cannot be under anaesthetic.
It does sound like an awful ordeal to put them through, but personally i think the pro's out weigh the cons.
It reduces the risk of infections,cancer even, and also unwanted pregnancies.
If you dont have a male dog, and really dont want to have her done, then dont. But i promise you they heal quickly and are back to noramal within a couple of weeks.