I've had both and in between!
My first birth was great, but much more overwhelming than I expected, and I did have some hemmorrhage which scared DH half to death, so although it was beautiful and she was perfectly healthy, I wouldn't call it a dream birth.
Second birth turned into a nightmare when it was discovered that he was surprise frank breech and coming very quickly - the midwife was not experienced with breech and for a few minutes it was frightening chaos. He was born depressed and had to be recusitated, had Apgars of 1 and 2, and spent 4 days in NICU.
Third birth was my ABSOLUTE dream birth, though! We made it to the birth center just in time (it's 1 1/2 hrs away) - I was 9 cm when we arrived and labor had been a breeze, not getting really intense until AFTER we arrived and I was in the birth tub. I started to feel "pushy", and 3 minutes later he was out! He was perfect, neither of us had any complications, and we were back home 7 1/2 hrs after his birth. Lots of other details that just made it clear that God was all over this birth, too.
During that pg I had imagined over and over having a very fast and easy labor, birthing in the water, and having absolutely no problems and it all happened just like that!