I've used smart launcher in the past, and even own the pro version of it. I do like how the "tabs" are organized on the left instead of across the top (in nova launcher prime) Though, I like more how I can organize my apps into tabs and then an alphabetical list in Nova Launcher Prime. It makes it easier to sift through all my apps. Plus, I've grown to love the multiple pages of docks that Nova Launcher Prime provides. I can put my phone, web browser, messaging, and camera apps on the primary dock, and then slide the dock to either the left or right (I've got three pages setup right now) and then have access to my most used apps, all while keeping my actual homescreen clean and uncluttered. The only two things I can think of to make Nova Launcher Prime even better, is to be able to move the app drawer tabs to the left of the screen, and when in list view, have the letters of the alphabet along the right side of the screen to quickly jump to that letter. (Right now, you can run your finger up and down the right side of the screen, and it will scroll through the alphabet, but doesn't jump to specific letter, so it is very easy to scroll past the letter you want to stop on.) I don't know if the features could be added, because I've heard from some sources that Nova Launcher isn't being developed anymore, and I've also heard that it will be developed more.