I've been using Nova for a long time. Simple and powerful at the same time and it doesn't use much battery or memory. Features like gestures, swipe up actions, activities and backups are a must for me. But a launcher is a very personal choice. Some will be dynamic automatically organising your apps, others will support fancy 3D animations and so on. The best thing to do could be trying the free version of different launchers and then decide which one suits your needs better.