For context, I got started with Illustrator 9 as a teenager (this is making me feel dated, it was released in 2000), and I'm very familiar with the Illustrator UX and find it intuitive.
When using Inkscape, the UX just feels slightly off, things like:
- Weird keybindings, e.g. pressing Ctrl +/- does not zoom/unzoom
- The golden path feels buggy. When launching the window is for some reason cropped to the top 1/8th of the screen and needs to be resized, and the artboard is tiny.
- Usability issues, such as selecting paths does not show their outline, and the layers window doesn't show a preview of what's in each layer
- Exported SVGs are needlessly verbose. This looks like it has gotten better but is still there. For example, exporting an SVG with two gradients actually puts four gradients in the file (combining with inheritance).
I'm sure that spending more time with it would help, and Inkscape does seem quite powerful, but UX is a big factor when I adopt new tools and Inkscape is lacking there.