I use it fairly frequently and enjoy it! My instance is Pxlmo but it hardly matters, federation doing its thing and all. The official app is quite buggy atm, but not unusably so, and it's fun to watch the updates slowly improve things. I do follow a lot of people who are actually on mastodon but only ones who mostly post pictures anyway, so they fit better in my pixelfed feed.

EDIT: Oh, I forgot to mention! I also kinda use it as image hosting for other apps! Only for pictures worth posting though, not trying to clutter it up. All my picture posts on Lemmy are stored there. If you put the direct link to the pic in the Lemmy image field, it shows up just as if you'd uploaded it directly to the post, no click-through necessary.