Ellie, both mine slept fine. DD was prem and in scbu for a month so was already in a sleep routine by the time she came home, but with DS after the first few nights of him falling asleep after the middle of the night feed, then crying as soon as I put him in his moses basket, I started to co-sleep and I'll be completely honest, most mornings when I woke up
I didn't even know if he had fed in the night. He would roll over slightly toward me, suckle, feed and fall asleep, then just roll away from me in his sleep.
Much better than the times I sat up on the sofa with Dd giving her a bottle and falling asleep holding her sitting up (really dangerous!).
Although I love the co-sleeping thing, I also love sprawling out and sleep so being able to get into bed without baby attached to me as such is important, hence the sidecar.
Both of mine have always slept perfectly fine as well, and ate fine too, I'm positive it's because I have been relaxed about it all.
Again, I'll reinforce what Peachy said about imposing feeding routines on babies, their tummies are TINY and can only hold so much, if you force them to feed when they aren't hungry you can give them bellyache and constant forcing will eventually artificially stretch the stomach, so even if you're FFing, I'd suggest doing it on demand for at least the first month or two.