I'm using QucsStudio from Linux, through WineHQ, and it works just fine.
I like QucsStudio because it can attach sliders to components, and visualize the results live, while dragging the sliders' values with the mouse (this feature is called "Tune"). Other than that, I prefer LTspice, which is free to use for non-commercial and is maintained by a company (QucsStudio has only one developer).