Koreader is pretty intimidating at first but once you dig into its features and know what's going on, it's pretty easy to navigate into the menus. It require some time to invest at first, but after that it's really "set and forget" with some lovely features and power to customise absolutely everything. I love the statistics wallpaper that shows you how much you read previous 7 days, per day, and the fact that you can set every book parameter as default, making every epubs looking the same, something I've never been able to achieve with stock Kobo, where I absolutely hated beginning a new book and discover huge fonts, weird margins, and tiny line-spacing, that I had to set again.