It's a common question especially among direct marketing junkies. Let's start here. Apple vs. Microsoft. I honestly can't tell you which is better. I don't know from personal experience. Yet, I don't know a Mac (Apple) user that isn't a die hard fan of Apple. I can't say the same about Microsoft users. Apple puts a lot of attention on the design of their products. I'm pretty sure that's due to Steve Jobs' fanatical commitment to design, but that's not the point. The point is Apple gets a lot of slack from their customers because of the design aspect of their products. Studies tie attractive design to positive attitude. So, Apple's products might not be all that much better than Microsoft's but they get slack because their users tend to be in a more positive state in regards to their product.
I have a friend that seems to be in the shop with his Mac all the time, yet he wouldn't dream of switching to a PC.
What does this have to do with your business???
Attractive design isn't everything. That's apparent in every aspect of life. (i.e. the attractive person who lacks between the ears) Yet, if you can wrap the substance that your business delivers to the market with attractive design that compliments your substance you'll find your clients will be much more positive toward your business when the inevitable mistake occurs.