Not good. Actually, the Frisco Market Buffet is the worst buffet that I have had in Las Vegas (or anywhere, for that matter). Nothing looked good, nothing tasted good. As others have said, the food looked like it had been sitting out for hours upon hours. The items that looked safe enough to eat were tasteless or dry. Even the desserts were stale.
There are so many other decent buffets in Vegas - even less expensive ones. I recommend passing on the Frisco Market Buffet inside of Arizona Charlie's and finding your way to...well, anywhere else.