I have used it in the past with good results. I used to feed Big Fella to most of my larger cichlids, but they recently made the pellet a bit smaller than I'd prefer for 8"+ fish.
I've still got some Big Fella in stock, if you want it, Craig. Let me know -- not much.
As far as a basic pellet or flake food goes, I don't think anything on the market beats X-Treme. I don't sell it well enough to continually carry it, though.