One of the best enhancements to gameplay SkyUI provides is several advanced features for the quick menu. You can now assign items to number hotkeys to quickly swap out items without pulling up the menu, and even create item sets to be able to completely swap out all your equipped items instantly with up to 8 different sets. This completely changes how you play the game as it's now feasible to have multiple item sets for different play style, such as instantly switching out from warrior armor to sneak clothes.
You can easily switch between your inventory and the merchant inventory by pressing alt, instead of having to navigate up and down a list, this also allows you to swap between you and the merchant while maintaining the category you are looking at.