I have not had any issue's with APW3's. They are what Bitmain recommends with S7/S9. I personally have followed this and not had any issues on the PSU side. They have kept working for quite a while now on some as I sold S7's and kept the APW3's. They can power even the batch 1 S9's which had the highest hashrate's.
There will always be market of server PSU's with breakout boards out there. But until I have a problem I will keep using APW3's as far as S9's at this point. I am not knocking some of kit's out there as I have not tested them. So just making clear not knocking them just saying what has worked good for me.
At this point a lot of my ATX psu's I had laying around from previous gen miner's went to mining Ether. I have had a decent variety of PSU's over the year's. If you have the 205V+ it is the one I would go for. If under the 205V then I would look at the EVGA Supernova 1600 you mention, as EVGA does have some great highend PSU's.
Thanks for your input. Can i ask how long have you been using those APW3s? The reason why im afraid to use APW3s is because i'm afraid that it would breakdown after the warranty expires.
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Since the launch of S7's, at that time I decided to use APW3's and so far I have not regretted it. They should last long after warranty if you have the luck I have had. A LOT of these psu's are out there and there are many user's. Also I figure Bitmain themself use them in internal mining facilities.... I don't think they would use them if big problems.
So I don't think you will regret decision as long as you have 205V+ and use a proper power cord. You do provide your own cord for the APW3's as there are so many different options depending on setup/pdu/etc.