I think I played with ponies and barbies pretty equally. I guess I have loved, and always will, My Little Ponies more, but Barbies are fairly special to me too.
My grandma got me those special collector's editions Holiday Barbies every Christmas. So, I got into collecting at an early age. Like, I looked forward to getting my Holiday Barbie every Christmas. And I don't recall ever wanting to open them up; they sat on my shelf, looking pretty. I still have all of them MIB...except the one my cat knocked over. She's in her box still, but the plastic was so brittle from old age it shattered like glass.
I probably have about the same amount of Barbies and MLP's. I would use the Barbies as my Megan & Molly. Although, I tended to like the brunette/red-heads better, so I used Chelsey & Katie instead of Barbie & Stacie. I played with my ponies more often, but my little sister was really into baby dolls, so I think I tried to get her to play barbies with me - I had a lot of barbies, but no baby dolls. I never got into baby dolls.
Anywho. I definitely liked my ponies more, but barbies were pretty special for me too. And as I got older, I played with them more. They would play the parts in my life that I wish I had gotten to do. I played with barbies until I was in like 7th or 8th grade...My best friend became one of the 'popular girls' and I kinda got pushed off to the side, so the barbies were the girls in school I wished I were friends with so my best friend wasn't embarrassed by me. One barbie I always used for myself, and then all the other ones would invite 'me' to the parties and all the stuff I didn't get to do because I wasn't 'cool' enough.