We introduced Alex to the "big boy bed" about ten days ago. The biggest issue we have had is falling out.

He fell out twice the first night, once the second night, didn't at all the third night, and at least once each night since. Mind you, this might also have something to do with the fact that he's getting four teeth this week..

We've also had an issue (last night) with sleepwalking?!?!?

Apart from that, he now WON'T sleep in his cot. He will in a portacot at a friend's place, but at home it's ONLY the big boy bed. He cries for hours in the cot.

Best of luck!