Awesome work!
Just a few minor things, that are already said, a scoring difference between series and films would be awesome.
With the movie Captain America: Winter Soldier, I had a problem, see below, cause the filename is reversed, I keep the original filenames, but the folders have the correct name.
Maybe you can use the title from plex instead of the filename, if the filename has no match for example.
2014-08-08 15:55:32,217 (-4d876490) : DEBUG (__init__:82) - Download best subtitles using settings: min_score: 50, hearing_impaired: False
2014-08-08 15:55:32,218 (-4d876490) : INFO (logger:29) - subliminal.api: Listing subtitles for
2014-08-08 15:55:32,219 (-4d876490) : INFO (logger:29) - subliminal.providers: Listing subtitles with provider 'podnapisi' and languages set([, ])
2014-08-08 15:55:32,219 (-4d876490) : DEBUG (logger:21) - subliminal.providers.podnapisi: Searching episode {u'sK': u'462x 3CA ST DH p027 4102 reidlo s retni w eh t acirem a niatpa c', u'sJ': 2, u'sXML': 1, u'sY': 2014}
2014-08-08 15:55:32,221 (-4d876490) : INFO (logger:29) - requests.packages.urllib3.connectionpool: Starting new HTTP connection (1): simple.podnapisi.net
2014-08-08 15:55:32,341 (-4d876490) : DEBUG (logger:21) - requests.packages.urllib3.connectionpool: "GET /ppodnapisi/search?sK=462x+3CA+ST+DH+p027+4102+reidlo+s+retni+w+eh+t+acirem+a+niatpa+c&sJ=2&sXML=1&sY=2014 HTTP/1.1" 200 None
2014-08-08 15:55:32,342 (-4d876490) : DEBUG (logger:21) - subliminal.providers.podnapisi: No subtitle found
2014-08-08 15:55:32,343 (-4d876490) : DEBUG (logger:21) - subliminal.providers.podnapisi: Searching episode {u'sK': u'462x 3CA ST DH p027 4102 reidlo s retni w eh t acirem a niatpa c', u'sJ': 23, u'sXML': 1, u'sY': 2014}
2014-08-08 15:55:32,462 (-4d876490) : DEBUG (logger:21) - requests.packages.urllib3.connectionpool: "GET /ppodnapisi/search?sK=462x+3CA+ST+DH+p027+4102+reidlo+s+retni+w+eh+t+acirem+a+niatpa+c&sJ=23&sXML=1&sY=2014 HTTP/1.1" 200 None
2014-08-08 15:55:32,464 (-4d876490) : DEBUG (logger:21) - subliminal.providers.podnapisi: No subtitle found
2014-08-08 15:55:32,464 (-4d876490) : INFO (logger:29) - subliminal.providers: Found 0 subtitles
2014-08-08 15:55:32,464 (-4d876490) : INFO (logger:29) - subliminal.api: Found 0 subtitles total
2014-08-08 15:55:32,465 (-4d876490) : DEBUG (__init__:87) - Saving subtitles to filesystem
2014-08-08 15:55:32,467 (-4d876490) : DEBUG (model:225) - Serializing to /var/lib/plexmediaserver/Library/Application Support/Plex Media Server/Metadata/Movies/1/3263132f9a893d54a9d6d1173949dacae64b0e6.bundle/Contents/com.plexapp.agents.subliminal/Info.xml