I gave a presentation to a #hamRadio license course audience regarding used radios. I recommended, and still do, to consider buying used rigs. I talk about different kinds of rigs and explain some measurement values (particularly IP3) and what they say about rig quality.

That talk is 10 years old now. The material it presents is good to know if you're interested in pre-SDR rigs.

The talk is in German. Lasting 100 minutes, it is also quite a mouthful.

https://media.ccc.de/v/afu-001