I'd like to revisit it. I first downloaded Qucs about 2 years ago and tried it out then. It was a little quirky, many things didn't work, and it crashed alot (which made it tedious to use) but I was most impressed the RF features and s-parameter features, which I ended up using the most.
I watched the video. It was not really a great demo, but I see that it's improved, and there are active developers so that's good.
I'll give it a try again.