Amazon does a superb job merchandising books. The free 3G wireless previews are a terrific way to encourage more sales. The user comments, the "if you like this you might like that" recommendations, and excerpts from published reviews make it easy, fun and informative to browse.
Kobo's bookstore, and desktop application, are severely lacking in comparison. The upside is there are some titles available at Kobo that aren't in Kindle format, especially for Canadians. Kobo has shown it is working hard to make improvements and is committed to an evolving product. I don't think they are chintzy: they are just getting off the ground.