If power cost are at .04 and the mining rig is operating at 1-2 petahash it seems profitable even at the lower BTC value.
If you have an immersion cooled datacenter with next gen chips (0.2w/gh) then maybe.
Current gen hardware will not be profitable and a datacenter with 1ph would require massive amounts of electricity.
Also please buy a cheap miner to start off with. Not sure what is up with the amount of noobs who want to dump loads of cash on something they barely understand.
Just to be clear, don't invest. You will lose. And calling it an investment is even a bit of a stretch. Gambling is more accurate.