I wore a pair about four weeks after birth because I had a funeral to go to and the only appropriate dress felt as though it needed a little bit of help to look ok. It wasn't that bad wearing them, but as I'd had a c-sec it was more because the scar got a bit warm and itchy.
They help, obviously, Spanx always help you look a little flatter tummied. But I only wore them because I already had them in the wardrobe. I never felt the need to wear them at any other time - you have a newborn baby, your tummy is never going to just pop nicely flat again. It's a good excuse to not worry too much about how your clothes fit!
I got a really sexy looking orthopaedic corset thing of amazon for £20. Best £20 I ever spent, they work. After two weeks I didn't look as though I'd had a baby at all with my clothes on. Let alone a massive 9 pounder out of my size 8 frame. They don't help with stretch marks or the weird brown line down the middle though, and if your skin gets really really stretched I'm not sure how effective it would be.
no. Sorry, I was being sarcastic it looked awful! But it did do the job and stopped my back aching which is really what I bought it for http://www.amazon.co.uk/DELUXE-POST-NATAL-ABDOMINAL-SUPPORT/dp/B001ILWO7M/ref=sr_1_6?ie=UTF8&qid=1354892224&sr=8-6