I had a friend that had implants put under the muscle. She told me that she would have never had it done if she had known the amount of pain that she would be in. I think it really depends on what, exactly, you have done.
I had implants put in under the muscle almost 9 years ago and it was a very easy recovery. I've never had a C-section but I was up and about normally within 2 or 3 days. Very easy recovery, better than my 3 vaginal births even!
I haven't had a c-section, but I've had a lot of surgeries. By far, my BA was the worst! I had them placed under the muscle and I went from a small B to a D/DD, which could be a factor due to all of the stretching. It was horrible! I was questioning why I did it for a few days and it was a good couple of weeks before I could open a door without pain.