I've had a Kobo Touch for maybe a year or so. I like it. It has a good electronic ink screen. It has wifi. I like the fact that it only does a full refresh of the screen after say 6 pages. The touch aspect of the screen works fine. The interface is intuitive and not ugly, like some others. I like that it only has one button, unlike others which have (or al lease used to have a multitude of buttons). It has a good battery life.
The Mac Kobo Desktop app is pretty and is easy to navigate. I had no trouble installing it. It works fine. The display of search results is a but annoying but the app itself is not buggy.
The website http://www.kobobooks.com is ok but the search can be unreliable - do a search twice and get different answers. Also do a search and get many repeats of the same book.
In summary I think the kobo Touch itself is a good product and the mac desktop app and the website are both OK. I can only assume that the Japanese desktop app had problems that do not appear in the english language version.