Curious which subsonic client? I’ve been using play:sun for a few years and sometimes AVSub. These clients are okay, but I do get some weird issues with them sometimes.
Having said that, I love subserver more than any other media server options.
I currently use iSub, but I’m in the same position: occasional weird issues, some that I think are compounded by my use patterns (I tend to listen on the subway, so the frequent network disconnects seem to break the cache.)
Having said that, I love subserver more than any other media server options.