I'm not familiar with Killer Tacos, is it on the waterfront? I've heard the name, but don't think I ever ate there.
As for Safeway, their deli makes incredible sandwiches, I'd rather eat there than some of the vastly overpriced places in Kona. Although Cafe Sibu is fantastic.
Killer Tacos is not on the Waterfront. Sibu is good.
Huggo's on the water is worth a try. We got for a late lunch (1:30 or so) after the crowd has left so we can get oceanfront seating.