I just tried Sortify, I've run it several times now and each time it randomly pulls a huge chunk of playlists out of those that WERE in alphabetical order (say L through M) and dumps them at the top of the playlists list in a random order, like throwing a deck of cards in the air...is that supposed to happen!?
Also, it doesn't sort within playlist folders, is it supposed to?
There should be a file called 'libspotifysharp.playlist.update.exe.config' open this in a text editor and add your credentials. If you don' t have a spotify username (ie if you signed up with facebook) you can reset it here - http://www.spotify.com/password-reset/ this should give you your username which is either something like 'ryantcarter' or a string of numbers.
Then you need to run the 'libspotifysharp.playlist.update.exe' file, just double click it and it should run in your command line, this little script is windows only.
At this point it's worth mentioning that users have been having mixed results with this script. It all depends on how your library is formatted. For me it's perfect as all of my playlists adhere to the schema of:
Artist - Title
The way it sorts is alphabetical based on the playlist name, if you have subscribed playlists it puts them all at the top, seperate to your other alphabetised playlists and if you have folders it can have some fairly wacky results. I don't personally use folders and it does the job for me.
I distrubuted it for free so if your mileage varies; then I'm not responsible for mixing up your playlists. 🙂