Rock and play safety?

So we got a rock and play and our lo is doing well sleeping in it (she would not sleep anywhere except in our arms) but now I'm a little concerned because I read some information and mixed reviews about how baby should not sleep in them too much as they are inclined a little and baby should sleep flat not inclined and that the surface is not flat enough for baby regarding sids guidelines. I also read that some babies got flat heads or neck troubles from them. So now I don't know about it. I monitor her sleep in it but still concerned about the information. We have plenty of time out of it but I was hoping to use it for longer stretches of sleep until we can try to transition to the bassinet or crib again and have it be her go to sleep spot for now but I don't want to think I am putting baby in danger or doing something that can cause head/neck problems. I will bring it up to pediatrician but I just wanted some opinions on it?