A professional looking website certainly reflects well on a customer.However, I once bought a car new from a website which was pretty poor looking. The reason i did that was because the new car was the least price compared to all the fancy websites selling the same thing. the only thing the poor looking website did was make me triple check the validity of the business behind it before i gave them 12k cash. But the thing i took away was that maybe they were cheaper because they hadnt spent so much on their website? Was it safer? Kind of - because it made me triple check - i didnt take it forf granted.
But, times have moved on, the bar is setm, and your customers expect a good web experience.