It is not the "best" gear, it's simply the most effienct gear, I don't know what's your definition of best but to me the S19 pro isn't the best gear out there, because efficiency isn't everything, but that's not like a universal rule, it's just my personal opinion, what matters the most for me is ROI, i always pick the gears which has the fastest ROI, I don't care much what happens after.

Of course, I avoid gears that overheat like T9+, or gears that are very inefficient because power is always limited and I want to maximize my hashrate, also gears that are known to have high failure hash rate, but all those technical aspects aside ROI is the most important factor in my book.

The S19 pro seems to be a solid gear so far based on the reviews (it has some PSU issues that a few folks reported), but what's bad about it is the price, the ROI is way too much for me, for your power rate at current difficulty and prices, it's 12-13 months to ROI on those S19 pros, usually what you see on the calculator today is only going to be worse.

There are expectations, you can assume that difficulty won't go up by much, and that price will hit 100k in 2 months and thus you would ROI in say 6 months or less, that's always a possibility, one which I rather not bet on when making business decisions, the other possibility is that BTC price will remain the same or go lower while difficulty keeps going up, this will extend the ROI period, while that isn't a certain scenario but I rather bet on it than against it.

Keep in mind that most people think I am rather very pessimistic when it comes to the price of BTC, but I remember very well when I was telling everyone not to pay 15k for S19 pro a few months ago, but the charts were green, everyone was saying 100k and I must have sounded very stupid to say otherwise, here were are now, with S19 pro making $30 a day as opposed of $50, and I see that things will only get worse from here on.

So bottom line, 10k for S19 pro does not seem like a deal I would take even if I had 0$ per Khw power rate.