It probably depends on what SHA-256 based coin are you going to mine. If you'll use the rented hash to mine bitcoin alone, surely you will lose money because first and foremost, if mining btc with those rigs are profitable for the owner, he/she wouldn't lease it to others.
It doesn't matter which coin. He will still lose money.
If he was to go for an alt-coin then he could just trade and save himself the hassle.