I breastfeed because that's what these honking great big bags on the front of my chest are for :P Well, that and breastmilk supposedly being the most healthy food for babies. The early days were hard going because I was still in hospital and struggling with getting fifty different sorts of advice from fifty different nurses, but once we arrived home and had the kraamzorg (after birth care in NL) helping us, things went much better. I think it took about four weeks or so before I could really say that I was adept at breast feeding. I'd always assumed it would be instinctive and easy, but it wasn't! It's like everything else, a skill to be learned. On top of that, the pain in the first few weeks doesn't help much, but that's disappeared with time thankfully.
The downside for me has been always having to be the one getting up at night (partly my own fault though - I could have expressed milk so my husband could feed the baby, but I've been too slack

), and also feeding in public - what happens so easily and naturally at home for some reason in public becomes a case of utterly uncoordinated and self-conscious fumblings involving blankets and a small cushion with a kitten on it (oh yeah, and the baby). I've just never got the hang of it, so on these occasions will sometimes use formula one-shots instead, or just avoid having to be out of the house at feeding time (bye bye social life...).
On the whole, I've really enjoyed breastfeeding though. I love the closeness with my son, and I feel ridiculously proud about being able to nourish him in his early months. I feel a bit sad that breastfeeding must eventually come to an end, as he turns to more grown-up foods.