This is the presentation I gave at the 2012 IEEE EMC Symposium as part of the Global EMC and SI University, where I was a co-dean.
If you are looking for a simple, easy to use SPICE-like simulator with graphical input and output with the option of integrating parameterized variables and equations to post process simulation results, look no further.
And did I mention, QUCS was free?
I think QUCS is an essential tool for all engineers. It is not a substitute for a high end EDA tool like Simbeor, or Hyperlynx or ADS, but can help you get to a good answer quickly.
In this presentation, I give an overview of simulation and the place for QUCS. This introduces the hands on labs developed to get a new user quickly up to speed. These are free to anyone and can be accessed through the hands on lab menu pull down under Signal Integrity Library on this web site.