I had a bilateral mastectomy and immediate DIEP on January 21, 2008. It was a 12 hour surgery and I woke up in incredible pain. Honestly, it was the worst pain I've experienced. I developed an infection in my breasts and required a second surgery a week later. The first three days were hell.
I spent two weeks in the hospital and when I left my body looked and felt beat up. My arms were sore but I could stand up straight and get around easily. I slept in a recliner because it was far too difficult to get in and out of bed. I had drains for six weeks and while they were an annoyance they weren't as terrible as I had feared.
My surgery was an extreme case. My pain was worst than most and I was slow to heal. With all that said, I would do it again in a heart beat. Two months post-surgery I felt better than new. It's a hard procedure but totally worth it.
Just be prepared that you will be a mess the first week in the hospital.
Feel free to ask questions.