Better UI design isn’t just touchy-feely designery stuff, it minimizes the number of annoyances in your application and boosts your product’s business value. You’ll get more users from word-of-mouth, your sales efforts will be smoother, and your user churn will be lower.
Last year Basecamp experimented with running ads on Facebook, Google, and Twitter. All-in they spent 6 figures on the experiment. And then they stopped. But what stopped them wasn’t the spend, it was the feel.