You're absolutely right Jennifive. Choose what makes most sense from a performance vs price perspective. I was in the same situation as you a few months ago. The 1070 were selling for £350, the 1080 for £380, the 1080Ti for £700... lol.
I went for 5x1080, logically.
Hello, can you share what hashrates / power consuption you have on algos you tried to mine?
Because I can buy 1070 for $540 or 1080 for $590.