My wife and I did the whole switcheroo thing. We had planned for me to be the one to carry/birth all our children even though we knew I had PCOS and would need clomid to get pregnant. We tried with me using a known donor for...15 months I think? We ended up switching our first donor to a second donor and then back to our first again because we had to move in the middle of the process. And I had at least two, possibly three, miscarriages all before six weeks even with progesterone supplements. The whole thing was just exhausting and heartbreaking.
Switching from insemming me to insemming DW was my idea. She and I are the same age (26 at the time) but her cycles are textbook perfect, as if they were invented by Toni Weschler for demonstration purposes, so we had every reason to think that DW would get pregnant very quickly. We decided for both of us to insem each cycle until one or both of us turned up pregnant (this somehow made sense at the time -- we were a little strung out). DW got pregnant on the second try by a donor who turned out to have pretty signifigant male factor issues. We were both ecstatic; I didn't have even one speck of jealousy when the second line turned up. However, once the obsession of TTC was over, DW and I both went through a grieving period for our plans for me to carry our children. Those were the roles we had expected and things didn't turn out that way so it was hard, for both of us.
There was never a point where DW and I felt like we were in competition. When we decided to have my wife start insemming we were both just desperate for a way to get the TTC misery over more quickly. Though...I think some of the reason we didn't feel competitive is because we are hoping to have at least four children. I mean, we knew there were more chances for pregnancies if one or the other of us turned out to be really unhappy with the way things were the first time.
And now that my daughter is here I really don't care if I carry or birth any of our children at all. Even though now we have much better health insurance and could probably afford to go through the treatments I would need to get pregnant successfully. We ended up with this great division of labour since my wife got to do all the pregnancy and childbirth and I am the SAHP. Though we're with Jenmostoften in that if we could afford for one of us to carry the other's eggs that would be our ideal; one person provides all the genetics and the other provides all the nutrients and breastmilk.
I'm sorry this is kind of a disjointed novel -- I have been trying to respond since yesterday but I have an eleven month old with a head cold trying to help me every few words.