Beta 2 of the Unity/.NET client API has been releases. yay
There are very very few issues left - mainly issues with failover to http protocol if sockets fail. This will be fixed very soon for the final beta.
If you run socket only, then this is now ultra close to production ready state.
The SmartFoxServer is a complete backend system that is extensible and has been used for very large games. Disneys Club Penguin is using it for 12 million subscribed users. It has its roots in the Flash world, but can now be used with Unity also using this client API.
Pricing is very good and fair for indies. E.g. the pro version is free to use for up to 20 simultaneous connections and slowly goes up form there.
Change log for beta 2 is here:
» Feature: HTTP failover for bluebox support when socket connection fails
» Feature: auto cleanup and disconnection using IDisposable. Manual Disconnect call not required anymore
» Feature: in debug mode the client API now reports if a callback message tried calling an unset delegate
» Feature: connecting is now also async
» Improvement: a lot of null checks around the code to make Firefox happy
» Bug: refactored all async socket to use a manual threaded socket instead to work around a Unity/Mono crash bug
» Bug: properly callback on socketexceptions and connect when it fails
» Bug: fixed messages that sometimes got cut off in the middle when multiple messages got received (thanks AT)
» Bug: fixed 2 minor bugs reported on forums by AT regarding populating room variables and using floats as numbers.
Also added robustness check for null parameter in SendXtMessage
Download link:
http://www.smartfoxserver.com/products/download.php?d=61
If you have any questions about the API, dont hesitate to contact me. Also watch the next few Unity Developer Magazines for the SFS article series
(No - I dont get percentage of sales, and this has up to now been developed by me on a volunteer basis)