I personally haven't, but a friend of mine has recently. Fiction in her case, but I think the advice holds. Get an editor. Even if you are going to self-publ

I personally haven't, but a friend of mine has recently. Fiction in her case, but I think the advice holds. Get an editor. Even if you are going to self-publish like my friend did. It makes a world of difference in polish. She used Amazon Createspace by the way.