I have lots of posters, both store bought and home made, and 5 wall scrolls, and frankly a like them all. I guess it would depend on the price, and just HOW bad the quality of the scroll was. If it's mostly the same, I think the scroll would be good.
Poster, because although it maybe fragile you can always frame it. The risk is the same when you're transporting it regardless. What you do to prevent that is the difference. So I choose to have amazing visual quality for better enjoyment.
I always prefer wall-scrolls, easier to move around, and it doesn't miss to many fine details. A poster I would always frame, every poster I've had is otherwise way too hard to put up, and looks a bit bad (needs to be flattened)
Having two beautiful wall scrolls in my room (one I got for Christmas, the other I got from a Chinese restaurant lol), I don't think a wall scroll would take away from your art quality, if it's your art
i think your art deserves the high definition of a poster, and it's not hard to get a frame to hang it, which will also protect the poster. 20x30 isn't all that big to be honest, it's big but not unmanageable. still, if the scroll looked nice enough i would probably buy that on a whim over a poster just cuz of the novelty.
Poster! Unless you have a need to move and transport it or you like rearranging your posters/room often, I imagine the risk of damage is minimal. I mean.......it's going to be on a wall, isn't it? * V * );;