yes, it works ok - except that streaming to PS3 is crap, but that's donw to PS3 design), but have those guys never heard of relational databases - creating 250,000 files in order to "speed up searches" is a joke - widows indexer does that with 1 database file.
I shudder to think how many extra files & folders it would create if it was allowed into my calibre library.
now you could say: well, disc space is cheap, so who cares how many files it creates; but then you wonder why it's taking an extra hour every time you defrag/optimise your hard drive.....
I did keep it a while for movies, after forcing it NOT to index mp3s, photos, you could probably trick it indexing your books if you really want it to. you just need to somehow tell it that epub is a media file format & it will happily stuff your app data folder with hundreds of thousands of new entries
but seriously, Plex's
raison d-etre is streaming media for a library to a range of devices. you can't stream an epub!.
calibre already as a server option.