Well, from what I know the quality of the protein itself is definitely greater. Caseinate is I think the poorest quality protein. But it's definitely not going to absorb as slowly as caseinate. If you are going with some lean meat before bed I would eat it with some natty PB, as the healthy fats will help slow the digestion of it and keep it in your system longer.
Or you could just eat a bowl of cottage cheese.