I think it may depend as to which variety whether they grow quickly or rather slowly. For example, Singing in the Rain is very fast for me, Kopper Kettle very slow.
They are part woody and not as easy to divide as herbaceous peonies - most often needing a saw.
Bartzella, which used to be quite expensive, I have seen at reasonable prices in the past at my local Costco (potted plants, not bare root).
I've also seen large pots of it at local nurseries for the staggering price of $120 (if I'm remembering right).
Seeing something like Bartzella in Costco makes me think they might be tissue culturing them now. I bought a couple (I think about $20-$25 each) and they did flower correctly.