the T17+ 58TH / 61TH are good bang for buck at around $900 currently, also S17e 60TH which are similar price and will give ROI in around 210-250 days depending on shipping cost (assuming difficulty doesn't change much).
How is 250 days to ROI a " good bang for buck", it's more like how to waste your money in 250 days, plus those prices are in China, so you are looking for 100-200$ for shipping, still have tax and all that, but let's be optistmic and say it's a $1100 (no tax) for T17+ 61TH.
Daily profit = $4.65
Monthly = $139.5
$1100/ 139.5 = just about 8 months.
1- It's unlikely that difficulty won't go any higher despite what the price does for a period of 8 months.
2- It's HIGHLY unlikely that the gear will have 0% failure for a period of 8 months.
So my concnsulion which I am willing to take a bet on is that you will need at least a whole year to ROI that IF EVER, unless of course, bitcoin goes to 30-50k in no time, and still in that case holding
BTC would be a better option.
Someone with free electity should go with an used S9, so a few offers for $25-$30 including PSU in the U.S , that's 30 days to ROI if you have free power, be on the safe side and count 2 months to ROI , it's 2 months Vs 8 months (the best case sncerio of all those 17series), also statstically speaking, a used S9 has higher chance to run for 2 months straight than a T17/S17 to run for 8 months.
But again everybody treats the mining business in a different way, my main method has been focusing on ROI in the first place, based on factors that include difficulty, price uncertainty, gears failure, and etc. the safest route you take when investing in mining IMO is how fast will you get your money back before "the shit hits the fan", I still remember those 1st/2nd S17 batches, those who paid $4000 nearly 14 months ago, they paid just about a WHOLE
BTC thinking they would ROI in 6-8 months, and we all know how it ended up for most of them.
I am not trying to discourage anybody here, but newbies should be aware that mining isn't a game anymore, it's a business and most people lose money doing business, and those who have no clue about running a business shouldn't be mining anymore, unless you are doing it for fun.