You can download a free preview sample of the Kindle format from the Amazon website. For example,
this link will take you to the Spain Guide on the amazon.fr website, and you'll see the link for a sample on the right under the buy button. If you don't already have a Kindle you can test it on, you can download the Kindle for PC app from Amazon to view it.
I don't think any of the epub stores have samples so can't help you for seeing how the epub would look on the Kobo.