It's so hard to really pinpoint a single birth experience as a definitive ... I have friends who LOVED it. Seriously. One friend said she could have had 10 kids no sweat; looked forward to labour and delivery. She would be a surrogate in a heartbeat.
My experience is more to the middle I would say. Both of my labours were 12 hours, not super long but long enough. An 11th hour (literally) epidural in the first and natural for my second, to prove I was tough (yeah!) Birthing takes over your body, and you realize you have to give over to the power of the process. But it's so individual for each person. It is weird to imagine this little baby inside you; your body makes changes to accommodate them, not always comfortable; near the end you just want the baby to get born already!
I grew up on a farm though and saw birthings regularly - maybe that's why it seems natural as a process. But I remember feeling weird to contemplate it happening to me ... I'll grant you that! Experientially interesting though. Too bad we can't make men go through it too!