I loved the default theme, the splash screen, all of the customization options, and how lightweight it was, but it's missing some of the conveniences and polish of GNOME, KDE, or even LXQt and Xfce. Using an independent toolkit meant that none of my apps looked consistent, even after trying my best to find a theme that supported everything, and if I explored the settings beyond a surface level things started looking ancient and clunky.
Definitely underrated, and really impressive for how much they could pack into a desktop targeted at older PCs, but still missing quite a bit.