Before I ever get into "nitty gritty calculatoions" on what to buy, I take a quick gander here:

https://www.asicminervalue.com/opportunities


I don't think ASICMINER's sha256 rigs will ever ROI ( Break Even). That Equihash rig might - but it's way too high risk for me.

The only rigs I've bought  so far this year are 1x Baikal X10 and 1x L3+.