Comment by d3Xt3r
Aurora [1] - it's based on KDE and has a familiar UI, somewhat similar to Windows 7. My mum has been using it for a while now without any issues, and she does everything an average PC user would - web browsing, document editing, file/photo backups etc.
The main reasons I recommend Aurora is that it is immutable, atomic and semi-rolling.
- Immutable means your core system files are read-only, making it resilient to accidental file deletions and corruptions.
- Atomic means updates are done as atomic transactions - they either apply or don't, there's no chance of a partial/failed state, no scary "black screen" after upgrades.
- Semi-rolling means you'll always be on the latest version of the OS, with major versions pushed out every 6 months. The main difference compared to other distros like Mint is that you don't need to worry about doing a big and scary OS upgrade, as not OS updates AND upgrades are image-based and atomic, with no chance of dependency issues or conflicts. So as an end user, a major OS upgrade is treated like just another normal update and it makes no difference to them, providing a seamless update experience.
By the way, I would strongly recommend against Ubuntu and Ubuntu-based distros like Mint, because they all tend to fail at upgrades [2]. Atomic distros don't have this problem.