I had an emCS with my DS1 and chose an elective for DD as I was too scared of having a natural delivery, even tho0ugh I really wanted to.
When I found out I was pregnant again I decided that I wanted to have the natural delivery this time as it would be my last chance as it were.
I got a good, supportive doula, got the most proactive consultant on board and had a fantastic spontaneous labour and laboured on gas and air. I needed a little hlep with forceps in the end, but it was a very positive experience and exorcised the ghosts of my horrible labour and birth with DS1.
My recovery was so much better, although I was laid low with severe anaemia, I still felt better than after my elective and was up and about as normal after only a week or so rather than the five weeks from before. bubbaluv makes a good point though. My recovery after my emCS was pretty good (although i was younger and fitter then) and better than a friend who had a third degree tear with lots of stitches recently.
If your DD was big and never engaged, have you been checked this time for pelvic disproportion?
Also, if you are booked in for an elective and then go into spontaneous labour, you can still have your section, although you'll be prioritised after any current emergencies, unless considered an emergency yourself (hence the question about disproportion as this would make you more of a priority).