Guys, if any of you are using the S590/S390 with a Mac through DLNA, here's a DLNA server to check out.
I was using Serviio, and it worked very well indeed for my MKV AVC files. It did struggle though with FF/RW and next chapter search, were the video would often start stuttering. If you left it alone, or merely paused, it was fine.
That said, I tried Elgato's EyeConnect DLNA server. Wow, amazing. Again my MKV AVC files playback perfectly, but also chapter search and FF/RW works without causing any issues. Very impressive. You can download a 30 day trial of EyeConnect from Elgato's website. Another nice feature is, it has a direct integration to iTunes and iPhoto. Meaning that if you create a new playlist in iTunes or add a new Library to iPhoto, they show up automatically on the S590 through EyeConnect.