I am an ex AMD, now Nvidia miner - I used to use R9 290s. Their versatility and power, and the amount of cool software for them was great, but then the 10xx Nvidia cards came along and I had bought a 1070 for gaming and for an HTC Vive I stupidly bought. I tried it out for ETH mining just out of curiosity and it turned out that it hashed as well as or better than an R9 290x but used half the power. I live in a country where energy is very expensive so that it a big deal to me.
I don't know a whole lot about the RX cards and I have an irrational perspective on them because for me it was like they destroyed ETH mining. What I really mean is that when the RX cards arrived there was suddenly a huge amount of noobs on the original official ethereum mining forum endlessly talking crap about the best BIOS mod for an RX480, and the difficulty just went to the moon. I went from mining 5 ETH every 2-3 days to 1 ETH a week within about 3 or 4 months. But I'm just bitching now coz I sold a lot of ETH way too cheaply and should have HODL'd it.....
GPU mining is pretty depressed right now, and for some reason there are a ton of new almost identical DASH clone coins, most of which use neoscrypt, which are actually a little bit profitable - so that is where a huge amount of Nvidia hash power is. The rest of it is probably mining something equihash based. According to whattomine.com an RX 580 is about as good as a gtx1060 6GB at neoscrypt mining or equihash mining. I have no idea how much either a 580 or a 1060 cost right now (I got all my 10xx cards before there was this crazy supply shortage) but personally I would go for the 1060 based on power consumption. That's why I went away from AMD a year or so ago - they (AMD) seem to just ignore the fact that their GPUs are just so power-hungry. I guess that's because the GPUs are ostensibly for gaming and gamers don't play 24/7 so they don't care if their GPU is using 150W to achieve what a 1060 can do with 90W.
So if you pay a lot for electricity, you are better off getting gtx1060s than RX580s, unless 580s are MUCH cheaper. If, however your electricity is cheap then buy 580s if you want. I think that AMD are behind Nvidia in R & D just because Nvidia has more money but maybe the RX580 is a great mining card.
I have 4 x 1060 6GB (most of my other GPUs are 1070s and 1080s) and my advice about them is that if you are going to buy them - do A LOT of research because there is a lot of variation between brands and models. For example I have 2 MSI 1060 6GB "Gaming X" and they hash (at almost every algorithm) about 20-30% more than the other 2 1060s I have, but they use about 15% more power. I have no idea about variation between 580s, but I'm guessing that you want to get one with Samsung or Hynix GDDR5 memory if possible (not Micron).
It's a tough decision, especially now - good luck.
Thanks for sharing your experience! I've been mining with 1080 ti's and 1080 rigs...thought about expanding but I definitely don't want to pay the prices now days (I bought 8 1080 ti's @ $699 during xmas time and now it's like $900+, 8 1080 for @$489 and now it's like $700+). I built a 8 1050 ti rig recently (paid under $200 each for it) and even that now its priced around $250 (definitely not worth it @ 180mh). That's why I thought about AMD...
but it seems like there are still quite a few AMD GPU miners and that's why I want some opinions on it...
Jeff-