When you go to SF, your aim is to check out the city. Walking to Brenda's will give you an opportunity to check out the entire city. A walk through the Tenderloin is eye-opening, even in the harshest light of day, and that is the only time I would ever recommend not taking a cab.
It's worth the walk or drive. Brenda's serves all sorts of comfort food with southern sass and Cajun flair. Just come hungry because all their food is incredibly rich.
Start with a Beignet Flight if you can't decide. They're mostly sweet, but they'll work as an app or sub for a main, and they'll do just fine for dessert as well. The Crawfish is their most unique, a mildly spicy, gooey-cheese mix with a few tender tails. The Plain is a fluffy classic - sometimes simplicity is the sweetest. The Chocolate is rich, dripping with a filling of molten Ghiradelli chocolate - save this one for last. The Granny Smith Apple might be my fave, it's like a buttery apple turnover inside a hollowed-out fritter.
Shrimp & Grits, the slightly grainy, butter-and-cheese tradition, topped with fresh pan-kissed shrimp. There's a tomato-bacon gravy that pulls it all together. The texture is more like a warm salsa than a goopy gravy, and the acid from the tomato brightens things up a bit.
You don't need it, but a Sweet Watermelon House Tea is a surprisingly light sip to break up the heavy bites. The watermelon dilutes the sweet tea so it's not the same sugar-rush as the traditional supersaturated southern tea. That said, I might prefer the sugar rush sometimes.
I'm not sure I'd go back to Brenda's but only because SF has so many other options I'd rarely visit the same place twice. But if you're in the neighborhood or have the hankering, Brenda's is worth at least one visit.