Mine was fine - I too have heard that its easier birthing because its so relaxed down there.

The only time I felt pain from there (that I knew was SPD) was when the midwife tried to get me to lift my leg from the floor onto a bucket to open my pelvis up even more. I couldn't do it, but still managed to give birth in that position (on my knees by the bath)

But I have come to realise that the pain I felt that I thought was my c-section scar rupturing was the pain when they go to the front of your pelvis - that was from my SPD, even though I didn't know it at the time.