Basically, he's had no problem sleeping in it - provided we let him fall asleep in his rocking chair first. It's the oddest thing, he'll take his blankie and curl up in the rocking chair, and eventually we put him in his bed and he's there for the night. Doesn't even get out of the bed until we go in to get him in the morning.
My question now, is, A) why does he want to sleep in his chair, and B) what can we do to convince him to actually go to sleep in his bed.

Glad it's going well on an introductory basis.
My guess - since I haven't been there, done that - is a comfort level.
He's probably comfortable and knowing that you (or whomever) is there with him until he falls asleep.
When he went to bed in his crib did you put him down asleep?
Is he not getting out of bed b/c he's not waking and you wake him in the morning?
I personally feel that it is a big adjustment for children to go to a big bed..cribs are very comforting for them since they have spent soooo much time in them and some just aren't ready at an early age (not saying Robbie isn't just some aren't)
With my child, I'm in the if it ain't broke don't fix it in regards to his crib. He loves his crib and has never attempted to climb out. He's almost 2 and I have no intentions at this point of taking him away from his comfort. When he asks or at 3 things will change..but IMO why rush them. However, my thoughts may change with other children or depending on that child.
He'll get to where you want him to be in regards to his bed before you know it and it will be just time.
Good luck!
It's actually his own little child-sized rocking chair he's falling asleep in, not the one I use in his room. Should've made that clearer - whoops! That's what I find odd - he's never really sat in it before now.
He's always gone down awake - refused to be rocked from about 3 months on. We basically just lay him down, hand him blankie and turn out the lights. He's a kid that cries wanting to go to bed and doesn't appreciate being kept from it.
Part of me wants to go back to the crib, but my kid thinks he's superman and can climb in and out.
I personaly wouldn't go back, as it IS working , big boy bed. I found it cute that he falls asleep in his rocking chair. I think for him, it's a Comfy zone. Does he takes long to fall asleep?