How can I alter this awesome General Tso's recipe to make it healthier using less sugar?

I have found an amazing General Tso's recipe that is a big, big hit with anyone who's tried it http://ift.tt/1Pfj1s6

It uses quite a bit of sugar though. I was wondering how I can alter the recipe to use less sugar. Should I use blue agave or stevia? Is there another way to get the sweet without the downside of sugar?

TIA

bon appetit