I've been mining SIGT for the last week, profitability better than ETH and takes less power too.

What is your rig? AMD or Nvidia cards?

AMD RX 580s, Nvidia would be much better, but even with AMD it's more profitable than ETH especially it was going up for the last few days.

But the difficulty has gone up a lot as well.

The other problem is the ICE age or the diffculty bomb.