I'm mining Dash on Genesis I have 200MH/s.
Reading your post I realize that I use to earn $5 daily when Dash was $60 now that Dash is over $100 I still earn the same $5 a day.

That mean that the difficulty is also going up.
But to me I still think that is profitable to mine Dash.

I can't say much about BTC I never bought any mining power for that.