Gang,
I thought I'd take a moment to report in with my findings now that I have the Sound Blaster Z installed in my rig. I'm 5 days into the new sound card, and it has it's pro's and con's. Sound is definitely more positional and "expansive" over the onboard Realtek ALC1150, even with the X-Fi MB3 software. This has come somewhat at the cost of what feels like low-mid to mid range sound. I expect given enough time I could "EQ" that out, but I find it a bit annoying right now.
I attribute the expansive and immersive sound to two things primarily. The more advanced software of the Z, and the Z's time alignment settings. Rather than feeling like I'm sitting in front of the sound stage when listening to a 5.1 source I now feel like I'm immersed in it with sound originating all around me simultaneously.
I have a friend shipping me back my old X-Fi Titanium. I plan to put that in place of the Z and see how that sounds. It'll mean giving up the Z's dedicated 600ohm headphone jack however. That will affect my long term plans to use a set of Audio Technica ATH-AD700X's with it.
I'm still playing with the Z, and I might not send it back. My main experience with it thus far has been Bioshock 2 (2010) which is an older game. Bioshock 2 used the Unreal 2.5 engine which maxed out at EAX 3.0, we're now on 5.0. It also didn't support DS3D. I had occasional audio glitches like a complete loss of a sound layer. I'm attributing that to an issue between the game engine and Direct Sound drivers. I've not yet played with it in depth in Battlefield 4 or any other modern games.
Right now I'm testing it with Bioshock Infinite and Battlefield 4. I'll report back with what differences I notice in the audio between the older game and the newer ones.
Does anyone have any 5.1 game source materials you'd recommend I try out for basis of comparison?