I can only pay for 12 hours electricity per day so I will be mining Ethereum through 12hrs only, as a rig owner do you think it's worth holding on to my mining rig or I should sell the rig and bit coins instead.
Good question.
If the rig is paid off and power is cheap that those 12 hours turn a profit mine on.
If you owe money on the rig selling may be better.
Depends on what you got.