I don't tumble or clean most brass. I've been thinking about getting a tumbler, just not sure if its worth it or not. However, for my brother's 243 brass, I either chuck it in a drill and shine it with steel wool, or wash it in a mix of water, dish soap and simple green. No real purpose. It's just the only high-end ("match grade") ammo I load so I like it to look good. Everything else I just load for plinking or general shooting. I really don't care how it looks.
Although, clean brass does make it easier to see defects, splits, etc. That's the main reason I've been thinking about investing in a tumbler.