Vega FE, yes, has potential, but it's drivers aren't optimized for games, nor will they be anytime soon according to AMD. The actual gaming retail card, the Vega RX, which has been tested vs the 1080 by many so far, performs about the same, and is a bit cheaper. Vega FE I've seen tests where it's mowed Titan Pascals, handily, but not in games, in apps, as again, it's more of a Quadro competitor, and will be sold as such, and supported as such. That same Vega FE has been tested in various games, and in gaming, it's performance compared to the Titan, falls to far below the Titan XP so far.
AMD marketed the Vega RX - maybe marketed isn't the correct term, but it certainly put the rumors out there - the gaming card, as a Titan or 1080ti killer, for less $. It is less $, but isn't even close to beating either, and again, Volta will be out shortly, this year, and that will obliterate the Vega gaming card easily, as the 1080 is already matching it, while the current Titan Pascals and ti cards are far faster. Again, according to the dozen or so early tests that have been published online by various tech sites.
In other words, the actual gaming performance of BOTH new AMD wonder cards could be characterized as ho-hum, and that's being generous. I would have paid for Titan P/1080ti beating performance, and built an all AMD new system with Threadripper and Vega, but it looks like it'll likely be Threadripper and Volta for the next one.