I had a GPU upgrade in the running for a LONG time (start of spring), but I was willing to wait for AMD's latest generation before I made a choice after nVidia released Maxwell. The 390 was the most appealing in the price/perf domain, but it worked against building my rig for power efficiency. It was also frustrating to find any relevant data on 390 power consumption when all the reviews put ridiculously overpowered units in their computers. And the reviews themselves are pretty sparse. Ultimately, I'm really annoyed that AMD chose to drag out the release all summer (Fury X2 not withstanding).
In another Nano thread I said the card only made sense in the $450-500 range, and I stand by it. If it can best the 980 in performance (i.e. not just at par), I could probably rationalize $550. For $650...I feel like I wasted my time. To add insult to injury, the Nano reveal was a paper launch and the actual retail launch was two weeks later. I got damned sick of waiting. It happens once every 4-5 generations but nVidia earned my money this upgrade cycle.
Tonight I dropped in a GTX 980 Poseidon in my main rig and am quite pleased with the performance. It's a bit more beastly than my 7870, but that was expected. My tower's gaming load with the 7870 was 210W, with the 980 it's 275W. The 390 would've certainly forced me to buy another PSU. And after rebate processing I'd have spent $440...I can work with that. I'm not saying the Nano is a bad piece of tech, just bad marketing and/or pricing.