If DS has an unsettled night I give him cot play time in the day (when I'm putting his clothes away for example) - he bounces on the mattress, he has his cot-only toys there, he's magically settled again that night. If I don't he's unsettled again.

DS has a cotbed, I will sometimes climb into the bed with him and move myself when he's asleep. Actually, I climb in every night for his story and we snuggle up to read it which REALLY settles him well. But sometimes I need to get back in until he's properly asleep.

We co-slept for 10m until DS wanted to stop and he always started off in his own crib/cot, mostly because he went to bed before DH and me. I love co-sleeping; not only do I get more sleep because I don't have to get out of bed we get loads of cuddles. It helps to regulate a baby's system and thus reduces the risk of SIDS, it helps set up the brain chemical system so co-sleeping babies are happier babies as well as learning a diurnal rhythm; they may not sleep through but they know day from night. It makes children more secure and lets them know they can always turn to their parents rather than there are times you're not wanted - imagine knowing you're not wanted by your parents ever!

The main downside of co-sleeping with a toddler is getting kicked as he wiggles. That's the only one I can think of.

Also many children have trouble crib to cot, or cot to bed - the problems are a new place to sleep, not co-sleeping to not.