Enthusia - I'm no expert, just my experience.......
Pethidine - I had two lots of Pethidine with my DS - It just sends you to sleep. I was knackered and I loved it, it allowed me to get some rest during a very long, painful, labour, although it did not last long (about an hour). But, lots of women don't want to feel sleepy during labour, but I would have it again in a heart-beat.
Epidural - 'not painful on insertion' - hmmmmm, not my experience, it was horrible, but lots of women have no problem at all with epidurals and swear by them.
Not painful (i.e. not screaming out in pain), but very unpleasant with lots of discomfort, especially when (a) they could not site it properly and kept jiggling tube in spine about and (b) when it only numbed one side of me. But, as I say, this is just my experience - lots of women have no problem at all with epidurals and love them.