These are $650+ graphics cards, and as you might expect, they are all very good products. There aren't any poor choices in this group, and each one of them has its own particular virtues. Which one is right for you will depend on what you value. Let's review briefly, and you'll see what I mean.
We should start with the GeForce GTX 980 Ti reference design from Nvidia, which many of these brands still sell under their own names. Although each of the aftermarket cards improve on the original in specific ways, Nvidia's board and cooler design set the standard for everyone else. The reference cooler is relatively noisy—but only relatively so—and it doesn't spin down its blower to zero like the other coolers represented here. But it does direct all of the GPU's heat out of the back of the PC case, something the others only do partially, if at all. The reference card also lacks a backplate to provide extra protection on the back of the board.
Nvidia chose to omit the backplate and use a blower for a specific reason: multi-GPU configs. The blower removes heat from the enclosure, and the backplate provides room for another card's air intake. If you're planning on packing two or more—especially more—graphics cards into the same system for SLI, then I'd recommend giving the reference boards serious consideration.
For everyone else, EVGA's GTX 980 Ti SC+ is a clear upgrade from the reference card for single-GPU use. The ACX 2.0+ cooler is every bit as compact as the reference design, yet the SC+ is among the quietest cards we tested. The EVGA card is also the only aftermarket contender that requires only a six-plus-eight-pin power input, so it should work with a broader range of power supply units than the other cards. In a way, EVGA has set its own baseline for GTX 980 Ti cards with the SC+. The firm also offers more expensive 980 Ti variants, but this one is an easy choice that gives you a little something more with minimal hassle.
Gigabyte's GTX 980 Ti G1 Gaming takes a distinctly different approach. It's one of the two fastest cards we tested overall. The Windforce cooler gives this card a long, lean profile; it's not much taller than the reference cards, which will make it a good fit in enclosures without much Z height. This card is a little noisier than most thanks to its default fan profile, but the Windforce cooler is clearly very capable. The G1 Gaming runs cooler than anything else we tested, yet it's still quieter than the reference cards. Also, I'm smitten with Gigabyte's multi-colored lighting—not because I like to taste the rainbow, but because it can be made to match or complement the other LEDs in your build. The G1 Gaming also has that second DVI port, which could matter to some folks.
The quietest card of the bunch is easily the MSI GTX 980 Ti Gaming 6G. The MSI also manages the second-lowest temperatures under load, behind only the Gigabyte—and it maintains its quiet, cool profile when overclocked. In short, the Twin Frozr V cooler is excellent, part of a long tradition of MSI goodness. Despite relatively high default clock speeds, though, the Gaming 6G isn't quite as fast in the benchmarks as the entrants from Asus and Gigabyte. Still, I have admit: this board might be my choice for my own personal system. The performance differences at stake here are minor, and I appreciate the Gaming 6G's quiet running and flashy good looks.
That said, the Asus Strix GTX 980 Ti would have to merit serious consideration. The Strix is the fastest card we tested, both at its stock speeds and when overclocked, and it's second only to MSI in going easy on the decibel meter. Asus' new DirectCU III cooler is deadly effective, but you'll pay for it in case volume. The hulking Strix makes the other cards look tiny. Provided it will fit comfortably into your PC's case, though, there's very little downside. Judging by current listings, the Strix costs no more than the other cards, and Asus throws in a full year of XSplit Gamecaster in addition to Metal Gear Solid V. That's the most generous software bundle on offer here.
At the end of the day, the Strix is the best all-around contender in this bunch, and I'm making it my pick for a rare, coveted TR Editor's Choice award. Just be sure you measure your case before ordering one. If your system can't swallow a 12" long card that juts up 1.7" above the PCIe slot covers, consider going with one of the other options instead. You really can't go wrong with any of them.