Jenna has been in her big bed since about 16m cause she was battling the cot every night, it was just awful.
We have the end up the cot up against the bed, and we have her right at the top of the bed, and she's pretty good at staying put. She doesn't like the blankets on her, and tends to kick them off and move further up the bed, so often we hear her banging her head on the wall when she is sleeping.
She does the same thing in our bed though, so it must just be her thing.

She has only fallen out of bed once, but in saying that she has gone back to sleeping in her cot during the day. Its just easier at the moment cause she will talk for ages before she goes to sleep, and I was putting her back to bed about 4 times each day. Now I can just leave her and she settles eventually.
We gave Jenna a pillow at about 14m cause she loved the ones in our bed so much.