I have recently changed to Mezzmo from Twonky as I changed my TV from a Samsung B series to C Series and there are compatability issues with the new TV and MKVs on Twonky.
I have found Mezzmo to be quite customizable and plays all formats I throw at it but I am not 100% yet, I have two issues that are bugging me.
I have to keep restarting the Mezzmo service as Mezzmo will just start running very slowly. when it enters this "go slow mode" menus take about 30 secs to load and when I finally get a video started it plays for 5 secs, then buffers, then plays etc.
If I restart the service it usually comes good , sometimes I need to restart it twice.
The other problem I have is quite often after the service gets restarted the Samsung will no longer see the Mezzmo server.The only way to get it back is to delete the samsung from the device list in Mezzmo , restart the service (sometimes a few times) and let it detect the Tv again, obviously this defys the whole conveinience factor of the DLNA equipped TV.
My setup is as follows;
Mezzmo runs on a Windows Home Server
Samsung is a PS50C7000
Network is 1000m/b wired directly to TV (no wireless involved)

I hope there is a fix for this because the thought of going back to Twonky and remuxing hundreds of videos does not appeal to me.
thanks