Cura is a very popular and easy to use slicing software. It is an Open Source software made by Ultimaker. The novice 3d Printing enthusiast will generally find Cura simple enough to get started but powerful enough to use for a long time. Cura removes some of the chores of preparing G-Code by automatically performing tasks like “center” and “lay flat”.
A downside to CURA is that is increasingly moving away from Home-brew printers and relying on manufacturer printer definitions. This author is moving away form CURA for that reason.
Some of the newer more interesting features is the material handling. With material definitions getting it’s own management CURA has begun the abstraction of material specific settings away from machine settings. This is probably a good thing.