As of late I have been experimenting with painting on heavyweight paper. It has a different feel to it, and I am beginning to like it. I also like panels and canvas boards, when I'm not using stretched canvas. The thing that I do like about paper, is the storage space that it offers me to file them away. Eventually, stretched canvas can run you out of the studio, if you try storing too much of it.
With the flatter surfaced panels and papers, its not a problem storing large numbers of works in a limited amount of space.
For now, though, I move around from surface to surface as I need to. Seems like I just enjoy the different feels each one has.