No difference. Actually personally I classified the better brand cards as shown below and also the lower tier cards.
- ASUS
- MSI
- Gigabyte
- EVGA
- Zotac
Lower Tier (brands I try not to get)
- Powercolor
- Sapphire
- Leadtek
- Palit
Even though if Leadtek or Palit come out with 780TI and is cheaper, I would still avoid. Its not because of the branding but more of the Distro support and quality. So far I had good experience with MSI and for Gigabyte I heard great stories about them.
Personally when I purchased 3 pieces of my 780TI, I did consider MSI and ASUS. But for MSI, they had sticker on the screws which I cant get it as I be watercooling them. As for ASUS, to pay $200 more for them is not worth just for the LV status. So I went ahead with Gigabyte as I had great experience with them previously rmaing my mobo.
As for the Gigabyte 780TI OC you wanted is a good deal as it is a non reference design vs ASUS reference design. Good buy!