While I cannot comment on products that are not released, I can say on-board sound has moved forward a lot over the years, even for the non-Core3D.  I prefer the Core to the Realtek HD audio, but the HD is actually pretty solid on sound quality (@Tweaked, don't come in here and go all audiophile on that statement please ).  Personally I have had some issues with it getting the surround balance right, and that might be because I have an older speaker system (good sound, tons of bass, just very old in computer years) but for 2.0/2.1 I have had no complaints at all with the quality.

Make sure product description says it support headphone amp or you will probably end up with a audio chip with less features. Jacob said evga z97 Classified Core3D supports headphone amps but nothing on the product description backs that up. 
 
I see Realtek has a chip that supports headphone amp but i don't think evga uses it.

This is nice option if someone no other solution... 
http://www.soundblaster.com/products/Sound-Blaster-X-Fi-Surround-5-1-Pro.aspx
 
I don't know I could not use any more something without at least Core3D or similar solution.
I use on SBZ, simply old boards with only basic sound you can't recognize who shot on you or where is enemy left or right...
you hear only some basic sound nothing else. 

On my Z77 FTW is similar sound as on X79 Dark, maybe even same.
I didn't know how that is bad before I hear Creative Sound Blaster X-Fi in other PC...
Than I decide to bought some sound card and now with Sound Blaster Z I'm satisfied.
I realize how is bad without sound card only when I hear sound from PC without sound card.
OK I have old speaker and sound could be even better but the worse things is because without sound card or
Core3D processor you can't notice source of noice, left, right, everything is same, only to recognize some noise.
No reason to everybody pay Sound Blaster ZxR and to pay 250$ for sound card but if we use expensive graphics at least some 80-120$ worth is enough.
USB 5.1 cards are excellent replacement. 
EVGA have Z97 Stinger with Core3D and Z97 Stinger with WiFi I think.
And now Z77 FTW + Sound Blaster Z that's excellent sound for games. 
 

#1 PCI Express-Attached M.2 
#2 DC-DC power brick
#3 Core3D or not
 
My number-one ranking.
 
 

Saw the new EVGA Z170 site... looks like the Stinger is being released with a Realtek chip. Maybe they will release an updated Stinger down the road with Core3D but I ended up ordering the new one anyway . Hopefully the ZiiSound T6 kit will hold up for now.

Nereus
no Core3D sound on the Stinger. Wonder why they went with Realtek? The Creative Core3D on my Mrs' Z87 Stinger is far better than the Realtek 8 Channel HD Audio on my X79 Dark, which is why I added a Sound Blaster Z card on my X79 Dark rig.. but no room for that on a Stinger. Not a fan of USB sound, plus it takes away the use of the front sound jacks on the case. Unfortunately this has made me rethink doing the Z170 Stinger build. Shame that a component so relatively minor can make such a difference. Scratching my head over EVGA's decision, at least on the Stinger.. guess Realtek offered them a good deal... may turn around to bite them on the butt though.

Yes, it is unfortunate that they did not go with the Core3D but like I said it could just be for this first model. I completely agree about needing a sound card but the ZiiSound T6 is pretty decent for USB audio (emulated 5.1 in movies/games is pretty close too!) for now. I will likely try using one of Creatives external sound cards (SBX G5 just announced) down the road and connect the internal HD Audio header with a converter / speakers with RCA to fulfill my needs (where there's a will, there's a way right?). Maybe there will be some M.2 sound cards in the future assuming it can be supported.
 
I'm already in the process of building my Hadron so I really needed to pickup the Stinger - now just waiting for the skylake's to fall and I can proceed.