If you were looking at Z87 / Z97, I would say definitely the Gigabyte as the a perusal of the Asus RoG Boards on the Hero shows a high instance of problems. It also didn't stack up well, performance wise, against the competition and had a high number of extremely negative newegg reviews.
http://www.overclock3d.net/reviews/cpu_mainboard/msi_z97_gaming_6_review/10
The ranking is based on setting the board which recorded the highest combined fps in the gaming tests at 100% and ranking the others by fps as a % of the fastest one.
MoBo % of Leader
MSI Z97 Gaming 9 - 100.00%
MSI Z97 Gaming 5 - 99.86%
MSI Z97A Gaming 6 - 98.96%
Asus Z97 TUF Sabranco - 96.13%
Gigabyte Z97X Gaming 5 - 95.00%
Gigabyte Z97X SOC Force - 94.95%
Asus Z97 Maximus VII Hero - 93.67%
Asus Z97 Maximus VII Formula - 93.58%
Asus Z97 Maximus VII Gene - 91.69%
Asus Z97-A - 89.57%
MSI Z97 Mpower MAX AC - 88.20%
MSI Z97S Krait SLI - 71.01%
I don't see MSI and Gigabyte hitting home runs here, just that outside of the Sabertooth Sabranco, Asus seems to have dropped the ball in this generation.
Another ranking appears below .... based upon which boards might be best avoided. The % listed are the percent of board owners who posted highly negative (1 egg) user reviews.
Asus Z97 TUF Sabranco - 3%
MSI Z97 Mpower MAX AC - 4%
MSI Z97 Gaming 5 - 10%
Asus Z97 Maximus VII Gene - 11%
MSI Z97A Gaming 6 - 12%
Gigabyte Z97X Gaming 5 - 14%
MSI Z97S Krait SLI 19%
Asus Z97 Maximus VII Hero - 19%
Asus Z97 Maximus VII Formula - 26%
Asus Z97-A - 27%
MSI Z97 Gaming 9 - 28%
Gigabyte Z97X SOC Force - 29%
The wide variation in performance, it must be said, is very unusual. The Z170s is a whole new ballgame and all Z170 reviews to date seem to have performance levels or all boards I have seen so far within just 1 or 2 % of one another. Withe Z170, we are not seeing Asus 7% behind the leaders this generation. It would appear therefore that Asus has returned to their expected form with this generation.
I still think the Z97 Hero is a pretty good board, it's just not a top performer and not a good buy at $210 ... not when it gets beat by and has twice as many highly negative reviews as the $125 MSI Gaming 5 which has an almost identical feature list and equal or better components.
Let's look at the newegg user reviews for your two named choices.... There are 37 reviews to date which is in the range where we can start to feel some confidence in the sampling size.... once ya get to say 100, confidence level is high.... below 20, it's tough to take much from it.
Asus Z170 Hero has an average rating of 3.4 eggs
http://www.newegg.com/Product/Product.aspx?Item=N82E16813132565
5 eggs - 38% (14)
4 eggs - 14% (5)
3 eggs14% - (5)
2 eggs - (9)
1 egg - 11%- (4)
Gigabtyte model seems to be a bit more popular with 44 reviews and has a significantly higher % of happier owners.
Gigabyte G1 Gaming GA-Z170X-Gaming 7 has an average rating of 4.2 eggs
http://www.newegg.com/Product/Product.aspx?Item=N82E16813128835
5 eggs - 64% (28)
4 eggs - 14% (6)
3 eggs - 9% (4)
2 eggs - 7% (3)
1 egg - 7% (3)
Using the compare function on newegg site.... these are the differences I observed.
- Giga supports 3867 to Asus 3733 RAM
- Giga has 3 SATA E ports to Asus 2
- Giga has 3 M.2 ports to Asus 2
- Both have high end sound solutions from different vendors, not in posaitin to judge which one excels as no data available that I have seen.
- Giga has Creative Sound Core 3D chip versus Asus ROG SupremeFX 2015
- Giga has 1 x Intel GbE LAN chip versus Asus Intel I219-V
- Giga has 2nd Qualcomm Atheros Killer E2400 LAN chip
- Both have 2 USB 3.1 ports
- Giga has 5 USB 3 ports to Asus 2
- Giga is $20 cheaper
I gotta say at this point that we are still in the early steppings of these boards and many bugs / problems will have been resolved by later steppings. Personally, we are recommending to users that they not jump into Z170 until the later steppings flush the earlier ones off the shelves which I expect will be sometime around the end of November.
But, if ya must buy now, with the data available to date, I gotta say go with the Gigabyte... it's got almost twice the % of 5 egg ratings, it's $20 cheaper and edges the Hero in numerous features.
As for the SLI's 970's, two 970s beat the 980 Ti by 20% and provide more bang for the buck... even when you include the larger PSU and even if you water cool the cards.
The alleged memory issue on the 970 has been shown to be a red herring.... test sites simply have not been able to recreate the reported problems. As long as you are not driving 4k, you won't have a problem. If ya need the numbers, the explanation and graphs, read this:
http://www.guru3d.com/news-story/middle-earth-shadow-of-mordor-geforce-gtx-970-vram-stress-test.html
If that doesn't do it, Extremtech put the 4 GB question to bed for good ... no issue at all for 4 GB till ya get to 4k and at the settings required to cause a problem at 4k game is unplayable. The reason people *think* it is an issue because what the utilities report as RAm usage is false. The tools merely identify that if the card see s 12GB it will "reserver" say 2/3 of that "cause its there"... it is not however used. Detailed explanation here:
http://www.extremetech.com/gaming/213069-is-4gb-of-vram-enough-amds-fury-x-faces-off-with-nvidias-gtx-980-ti-titan-x
Two 970s have no problem at 1440p... whatsoever... not in the reviews, not on the ones we've built. Here you see the 970s in SLI topping the Titan
On average the SLI'd 970s are about 20% faster than the 980 Ti when all are overclocked.
As for the monitor, if you are investing $700 in GFX cards, I wouldn't even think about not having 144 Hz / G-Sync .... It's often asked why G-Sync adds a cost premium and Freesync doesn't. It's because they are not remotely the same. Freesync basically provided synchronization below 60 Hz ... so does G-Sync.
But what G-Sync also provides is additional hardware which provides motion blur reduction or ULMB (Ultra Low Motion Blur). You can buy Freesync monitors with MB technology but that also comes at a cost premium... some monitors include it, some don't... some have a good implementation, some don't.
I play Witcher on twin 780s on a 144 Hz TN monitor... my son plays on two 970s on a 144 Hz G-Sync IPS Monitor (Acer Predator XB 270HU) .... I'm so frakin jealous