If you are someone that mostly likes the Windows 7/10 experience, KDE out of the box is basically that. It's more customizable. It's (IMO) less clunky and less burdened by legacy components. But it really just feels like windows used to feel like.
But also just fast and low memory. You can run KDE on ancient hardware. If you have something like 512MB of ram, you can do KDE just fine.
>If you have something like 512MB of ram, you can do KDE just fine
The past is a foreign land. Minimum memory requirement for Windows 95 was something like 4MB. I ran OS/2 on 8MB of memory (with a Cyrix 40Mhz 486 clone).