Ok, so I found something out today regarding digital sound output via optical. Apologies if this is old information and has already been discussed.
I planned on getting the EH5300 because it had 3 HDMI ports. I intended to hook an Xbox 360, PS3 and Wii U up to it via HDMI. I then planned to use the SPDIF/optical-out on the TV to pipe 5.1 Dolby Digital out to my receiver. I assumed the TV would compress the LPCM from the HDMI (whether 5.1 or 7.1) into a 5.1 bitstream for optical output. Turns out I was wrong about that.
After digging through the manuals for the EH5300 and the EH5000, as well as chatting to Samsung tech support about 6 different times just to be absolutely sure (I'm betting they hate me over there
), I can now confirm that these two models only output 2.1 audio over optical from any external source such as a game console, DVD/blu-ray player, etc. They said the only way to get 5.1 ouput from the optical-out is when using over-the-air HDTV broadcasts or from a coaxial cable connection from your cable provider. They suggested that to get digital audio from the source devices, you'd need to connected the device directly to a receiver.
That suggestion is all well and good for devices with an optical-out, but for things like the Wii U that only output digital audio over HDMI, you'd have to connect the Wii U to an HDMI receiver first (which I don't currently have, but I'm looking into upgrading), and then output the image back to the TV. The whole reason for wanting to hook things up the way I described was to keep input lag at a minimum. I know its been discussed that this TV is around 2 frames, but I was concerned about adding a device in the chain and potentially increasing lag.
Based on this info, though, I'm thinking I might just get the EH5000 now and pipe all consoles into the receiver first. I figure I'll save some money on the difference between the two screens, which can go towards my receiver upgrade!
Anyway, I hope this info is useful.