Direct quote from the avs forum. . .
"You have answered your own question. Neural is pseudo DTS:X, just the same that Dolby Surround is pseudo Atmos Most people, I presume, would use an Atmos speaker layout to take advantage of the upmixing. I use a 5.1.2 with a pair of upfiring Atmos enabled speakers. I find Neural:X to be very effective, especially so on live music discs where the front soundstage is greatly enhanced.
There is soon to be a firmware upgrade released that will allow cross mixing, so if you prefer Neural to Dolby Surround you will be able to use that on DD soundtracks and vice versa."