Re: If you have now 500$ for invest? Where you invest?
Furthering this question, what if you have $1500 today to invest? Would you buy 3 more graphics cards for an existing miner? Hope to find a BTC miner? Buy in at the next crash? This has been bugging me for some time now. 
For difficulty is rising too fast. It is better to just buy the coin itself.
I think you're correct Re: BTC. Difficulty is just moving too damn fast. I think I might buy another (or 2) 1070s to work on the smaller coins and buy more BTC after (hopefully) SegW.