IMO, the Kobo UI is greatly superior to Kindle's. The awful Kindle UI was the major reason why I switched from Kindle to Kobo a few years ago. If you've been content with Kindles, there's no reason why you shouldn't be very happy with the standard Kobo.
It's also possible to tinker with Kobos a bit if you find yourself so inclined after you've got used the UI.
1.
Kobopatch allows you to tweak the UI to suit your own tastes. For example,
"Remove footer (row3) on new home screen" will remove the advertising that normally appears just above the icons at the bottom of the home screen;
"Don't uppercase header/footer text" changes the book title at the bottom of the reading screen from all upper case to mixed;
...and so on.
2.
NickelMenu adds custom menu items to various menus in Kobo's eReader software.
3. Setting your device to Sideloaded Mode might be a bit extreme for you, but I've found that I like it. It disables Wi-Fi downloading direct from Kobo entirely (both books and firmware), and requires you to load books manually, using something like Calibre (which I favour) or Adobe Digital Editions. It also disables the home screen altogether.