Finally had a chance to give nzb360 a proper run with torrents and noticed a couple of bugs:

Setting speed limit to Unlimited in nzb360 actually sets deluge to 0kbps upload or download, deluge requires -1 to be unlimited

Deluge & rTorrent
Errored torrents don't show up in the Error tab, which shows "No torrents with errors." despite clearly showing errors in both clients.

App: 12.0.1
Android: 7.1.2 / API 25 / LineageOS
Just updated to 12.1 and the second issue, with errored torrents, is still present. I currently have 8 errored torrents in rtorrent, but nzb360 displays No torrents with errors. in the error tab.

Deluge has 13 errored torrents, but the same No torrents with errors. in nzb360.