I've always worked with LTspice, it's fast and intuitive, and it never failed me. However, I think it lacks lots of features, creating libraries of subcircuits is always a pain, and sharing them also. I work on Linux, so it's a problem also that I can't run it natively.
What are some other good circuit simulators that you can recommend? Be them open or closed source, free, expensive, I want to know what other options are there and the experience you had with them. I've seen most PCB software (KiCad, Altium, EAGLE, etc) have some kind of circuit simulation enabled, but I don't trust it's practical. However, I've never used them, so any opinions are appreciated.