I reckon it depends how long bub will be in your room for. DD was in a cot in our room for around 18 months I think. Then she went in to the cot in her room, but the size she was by then, the side was annoying. We took that off and put on a barrier thing.

Then I got pregnant and we decided to get the nursery ready for new baby, and made DD a new room. She has a Queen size bed in there and it's brilliant. If she does wake in the night and call for Daddy he has loads of room and they both sleep comfortably. That wasn't the main reason for the big bed, but we all love it and if I did it again I'd just move her straight from our room to there.