I was down there in September for my honeymoon and didn't really have time to seek out beer bars. There's a small brewpub on the V&A Waterfront. I wanted to get over to Brewers &Union but didn't have time. Found their beer (Steph Weiss) at a restaurant in the Gardens District and thought it was pretty good.
If you need any recommendations on restaurants let me know, but these will be more wine centric. Miss Cape Town, it and SA in itself is an amazing place in the world.