These are the only stores I buy from too. Amazon is amazing... lots of reviews and detail info about ebooks, really help customers buy. I can spend hours looking at the books, reading the reviews and book excerpts
Kobo store on the other hand is absolutely the worst of its kind. No reviews, no excerpts, won't tell you how long the book is... and sometimes, there's no download links! The prices are also almost always higher at Kobo vis-a-vis Amazon. The one and only reason I visit kobo site is to buy with the discount coupons. You can't really browse books at kobo store, unless all you want to do is look at book covers and blurbs.
I think Kobo is expecting customers to research at Amazon before buying from them. Kobo needs to improve its store to provide better customer experience. Relying on coupons to sell books isn't good enough imo.