Bitmain is no longer making T9s. If you are going to buy a miner from them it is an S9. There is no sense throwing money away with a USB miner.
This silly idea that bitmain is going to mine on your used hardware just needs to go away. They have literally tens of thousands of miners of theirs that arent even being put online, so why would they bother mining with your one single RMA unit?
Well when you think about it there's more than one unit being returned due to problems. I mean I don't know for sure, but just seems like a profitable idea if they're getting 100+ returns of "broken machines", but who cares either way just seems weird to me.
The only reasonable answer I would have for anyone buying a USB miner would be as a trinket. There’s little to learn about BTC mining these days as everything is plug and play and maybe a little knowledge of GUI information.
The whatsminer comes with a PSU for cheaper than the S9 iirc but it is less efficient as you just said. Depending on your electrical cost the choice is a little more difficult, but in general I’d go for the S9. Just keep in mind Bitmain’s support has been going steadily downhill and has maybe been slipping even faster in the recent months.
Okay, so do you personally mine and experience these difficulties with Bitmain? I'm just curious to hear from miner's experiences so I can account more risks before I throw money into this.