Well, I do both - I go for teeny plants, such as plugs, if I know it's a fast grower. Or, if I feel I can divide, I'll get a big pot. However, I killed a dicentra this year doing that, which was weird. Not that I don't kill plants, but it's usually not by dividing! Dicentra must not like to be divided - ??
Well, whatever. The first piece died and now the 2nd piece is on it's last legs. Er . . . roots!