
My girl was spayed last Tuesday, not sure what is the best age though as she is just coming up 6 now. She came home from the vet Tuesday at 4.30pm very sleepy and sad looking, slept most of the evening, came back to life a bit during the night, when she had a little boiled rice and chicken, next morning she had her painkiller Metacam, by Thursday morning she was completely back to her normal self, no longer needed the pain killers and to be honest you would difficulties believing she had just been spayed. She doesn't have her stitches out until Friday and I am having troubles keeping her from leaping about. :-)
Each bitch reacts differently, some tolerate pain more than others.
The only obvious dangers are the anaesthetic, which applies to any op and my vet kindly pointed this out to me as I was signing the consent form :-(
Good luck with what ever you decide, I'm sure she'll be just fine!