We've found a great article in Mark Hurst's Good Experience Blog. We re-publish an excerpt with his kind permission:

Which of these is a better experience?

In a restaurant:

When you walk into the restaurant, the hostess welcomes you warmly and takes you to your table. The interior decoration and overall ambience are attractive and comfortable; the food is delicious.

Or, at a different restaurant...
The restaurant is called "The Jungle Experience." Upon entering, the hostess asks you how many are in your "safari." As you sit at your table, a fine mist of water sprays from a sprinkler hidden in the plastic foliage surrounding the dining area. The menu items are all named after rare tropical animals. You have the simulated experience of dining in a jungle, although the food isn't very good.

On an e-commerce website:

You're able to access the product you want in a few seconds, thanks to prominent links with obvious titles. The search function brings back accurate and helpful results. The simple product page makes it easy to compare different products, and then it's easy to choose a product and check out. Overall, the experience is quick and easy.

Or, at a different website...
You're impressed by the attractive logo and the colorful appearance of the page. It looks similar to the colors and graphics in the TV commercials for the company's products. There are lots and lots of features available on every page. Everything has a very professional appearance. Overall, you get the strong impression that the company spent a lot of money on the website. Unfortunately, it's hard to find the product you want.

In each case, did you choose 1 or 2 as the better experience?

[...] The comparisons are important because they represent two different methods of creating a good experience:

In case 1, the company focuses on meeting the customer's needs at each moment.
In case 2, the company creates an "experience" with a "wow factor" in an effort to impress the customer. The customer isn't central to the experience, except as a consumer waiting to be entertained. The focus here is visual flashiness and gratuitous technology.

Which method does your company pursue more often?

If it's 1, congratulations: you're operating in the long-term interest of both the company and your customers. And knowing that, you have the added benefit of a meaningful job - creating some good in the world (even if only the business world).

If 2, I wish you the best of luck. You might get short-term gains in customers and publicity - but without a focus on customers' basic needs, your business won't be healthy for very long. [...]

In fact, companies who invest more in the "wow factor" almost always take resources away from focusing on those more important (if visually less exciting) issues.

But think back to the customer. After all, we started the column with an exercise in customer experience. If you - as a customer in each of those situations - had to choose between the basics and the "wow factor," which would it be? If you had to design the customer experience in each of those situations, and you wanted to maximize the long-term health of the company, which would it be?

It's important that your web site has a professional design and it's also important that your web site looks great so that your customers have trust and confidence in your company.

However, before adding bells and whistles to your web site, make sure that it serves the basics. Your customers must be able to find what they're looking for on your web site. Once you have achieved that goal, you can add more features to your site.