Some real stats from my rigs.
12 Cards 306.9 Mh/s
Minute: 0.00001
Hour: 0.00104
Day: 0.02505
Week: 0.17539
Month: 0.75168
So it's getting harder I used to get over 1 ETH per month. But if you view it as a hobby and enjoy it go for it.
As long as it is still profitable, it is still good to mine it. That is what I do.
Minute Ξ0.00003 $0.03 ฿0.0000
Hour Ξ0.00181 $1.54 ฿0.0001
Day Ξ0.04340 $36.95 ฿0.0034
Week Ξ0.30378 $258.67 ฿0.0237
Month Ξ1.30191 $1108.60 ฿0.1015