I'm not using them yet till Bean makes his appearance, but I always knew i'd use real nappies even before I thought about having a baby.
For me, it's the environment first- I'm quite eco friendly and green in general and try to minimise using anything disposable. The second reason was chemicals near my babys butt- freaks me out! And finally, the cost, although having spent a fricking fortune now on cuteness that's not a reason anymore!