I am needing some opinions on whats the best bang for my buck.  Here is my situation.
For the next 3 years i will be paying .01 kw for electricity.
i have an additional 20k to invest in miners.
I have already purchased 10 z11 antminers.
I know the havling is coming up in a few months.
Which miners would make more sense to buy? should i keep buying the Z11? Should i change to asic miners?
Do you think i should sell the z11 and invest the money in other miners?

Anyways i appreciate everyone help.