Diversification in held coins makes sense. Buying GPUs that aren't effective, efficient, and likely to have a good resale value is not a good idea.
Totally agree. 570's were effective, efficient and still have resell value, when you think of it. They gave most hash/dollar for quite a while during the ETH run up. And then profited nicely from the CN era as well.
1070's were very good too in that respect.