both. It more-so depends on if I'm happy with them; but more often then delete them, I'll move them to scraps but that's usually with older work I don't want in my gallery, but I don't want to delete because it was my "good" stuff at some point. I like to be able to show improvement.
Well its a weird way how things go here on deviantart. Sometimes i see really powerful pieces and they hardly receive a lot of views favourites etc. While a lot of the times i see pieces that and will say it nicely makes me scratch my head twice and they get so many views and favourites that it makes me think its a reverse world. Beautiful work gets pushed away by very very poor work and thats something that is sadly happening more and more. So thats why i leave my work were it is in my gallery and dont delete it. Its all personal preferences