yup S9s are quite good if you can keep them from dying lol, best thing. to do is order more than u need keep some in
reseve for the inevetiw faliures , i think they have a 30 percent failuer rate from the older batches, maybe new ones. are better tho, Thats why i ordered six, only needed 4 but two spares
With the current price of $1265 where you can (have to) buy by the BTC which you of course have purchased much lower price

it really is a good deal. Just look at it as an investment which will give you a pretty good annual returns.
In long term stock market gives you 9% p.a. so from this point of view S9 is way much better vehicle

btw. I recommend you to run all of your units fully and if something goes bad then it goes. You should get better returns by this way.