DS1 - it took about 2 months to stop being painful. I asked everyone I could think of why it was still hurting, and the most persuasive answer I got was that it was because I am very fair skinned.
DS2 - hurt the whole 6 months I fed him as I had thrush in my milk ducts which I couldn't shift. I thought I was being such a great mother by sticking at it but I was horrible to poor DS1 as I was in such pain
DD (7 weeks old) - stopped being painful after about a week, slight blip when I got mastitis but now it's going very well. I have a painful "let down" this time round which is a bit of a nuisance.
For me it feels like a gentle way of getting used to not being pregnant: you maintain that very intimate physical link with your baby.
With DS1 and DS2 it really helped me lose weight. Remains to be seen with DD!
I am really disorganised and have a grotty kitchen with no room for a sterilizer! I preferred being able to feed whenever, wherever rather than have to bring bottles out with me. If you don't mind feeding in public and you are likely to be within easy reach of somewhere you can sit down and feed, I think breastfeeding is really convenient.
It makes you sit down, and may give you the only sitting-down time you get all day.
My DH wouldn't do night feeds if I was bottle feeding so it probably gets me some extra sleep (not having to prepare a bottle).
Disadvantages:
Massive boobs so I look like a partially-deflated balloon.
I am rubbish at expressing (and can't find the breast pump!) so I can't leave her. Doesn't bother me at all at the moment but may do later.
I have a bigger appetite than when pregnant so really hope the bfeeding is burning it all off!
Enjoy your new baby when he/she arrives