Interesting question!
I don't know the answer or have an opinion, but I'd like to say that c-section births are generally harder on children physically than vaginal births.
Statistically, c-section children have to be recussitated more than vaginally birthed children, have more problems getting started breathing, have more fluid in their lungs, have a more difficult time nursing, have more drugs in their system and generally have a rougher start to life.
It might *seem* like just being lifted out would be easier, but it's not. The squeezing contractions expell the fluid from the lungs and the adrenaline rush in the baby's system prepares it to deal with the shock of being born, and switching oxygen sources. Also, breathing is more difficult if the umbilical cord is cut immediately - if it's allowed to stop pulsing naturally, it is a back up source of oxygen for the babe as it begins to use it's lungs. Babies who born by c-section are immediately clamped and deprived of that alternative source of oxygen, in addition to having a tube inserted down their throats into their lungs for deep suctioning, so they gasp for breath and have to deal with all the business of breathing immediately. Plus, they are usually taken to the nursery for "observation" (meaning they are put into baby buckets and stored until convenient) instead of being given to mom right away, so they miss alot of that immediate comforting and bonding time, and they generally have more tests done on them to make sure they are healthy (or not).
So, babies born via c-section *generally speaking* have a *rougher* start to life.
I had a horribly traumatic vaginal birth (twins 10 weeks early) and I remember 4 past lives and have glimpses of two more (I think). I'm not sure the manner of birth eliminates or accentuates pre-birth memories!