Sticking to one box solutions, the next step up would be a Bluesound Powernode or an NAD C700. Next step up in performance would be the NAD M10 v2, which looks to be currently on sale for US$2,499. All use the BluOS app which, by most accounts, is probably one of the best out there.
The "persistent queue" mentioned above probably refers to the fact that when you load an album or a playlist, it just gets added to the play queue. The play queue does not automatically reset. This makes it easy to create new playlists. The downside is that if you don't clear out the play queue (by merely pressing a button), when you load an album or playlist and hit "shuffle," it will shuffle everything in the play queue. For some reason, this feature seems to drive some users into a fit of rage.
Other all-in-one units out there are the Naim Unity Atom and the Hifi Rose RS520, but both are beyond your USD 3k limit.
I have an older Powernode 2 in a second system, and it is a pretty good sounding unit.