I'm going to try to make a few mini-lessons here on Csound. We'll see how this goes.
I'm assuming that you have never used Csound before, so I'll start from the beginning.
Csound can be thought of as a text-based modular synthesizer. Synthesizers are "built" inside of a text editor using modules called opcodes. Modules include various kinds of oscillators, filters, LFOs, and envelopes, but there are more unique opcodes for things like physical modeling, granular synthesis, additive resynthesis, and phase vocoding. There are ways to implement programming idioms, but Csound is not a programming language. This is a tool for musicians and musically-minded individuals, not a way for programmers to incorporate musical elements into their work.
I learned about Csound 4 years ago, and have been using it quite intensely the past year and a half. It is one of my most used programs for synthesis and sound design.
To start things off, I'd like to give four reasons why Csound sucks and is a terrible program to use:
1. It's old. The source code is an accumulation of over 20 years of work. It can be very difficult to incorporate Csound seamlessly with modern tools in a DAW. It has quirky old-timey conventions.
2. The score. It's a terribly old-fashioned text table with timings and other information which Csound will use to play instruments. Writing out note-sequences can be very time-consuming, and can be done much quicker in a DAW.
3. The orchestra. It's basically the section of a Csound synthesizer where you build the synthesizer. It's only text, so it can be very hard to read at times. It's very hard to come up with sounds quickly in Csound, since they are typed out and not "patched" or "twiddled."
4. Everyone in the Csound community makes strange music that's hard to listen to. It's rare that you find a (good) Csound composition with a beat, something in 4/4 time, or even something with western tonality! To me, the stereotypical Csound composition is droney, with shrill blips and scary clusters of notes.
Conversely, I also would like to give four reasons why Csound rocks and is an incredible tool for electronic music:
1. It's old. Not only that, but the community is very fervent on backwards compatibility. Csound compositions written twenty years ago can still run flawlessly on the most recent version of Csound. In the electronic music world, it is very typical to have to learn new software every 5 years or so, and to essentially lose any projects made with the older software (backwards compatibility is not a guarantee.) You take the time to Learn Csound, and your projects will be timeless.
2. The score. it's only a text file. One can very easily generate scores for your instruments in any programming language with file I/O (which is basically every modern programming language.) Your scores are not bound by the constrictions found in a MIDI sequencer. I'll get more into this later, but things like audio-precise timing and floating point resolution parameters.
3. The orchestra. It forces you to think at a very low level for sound design. Working with Csound, you will gain expert knowledge on how to make engaging and unique sounds with synthesizers. As an added bonus, this can be applied to any available commercial synthesizer.
4. Everyone in the Csound community makes strange music that's hard to listen to. And that's a good thing. There is so much easy music out there. Hard music is food for your brain. As a musician, it's the hard music that makes you grow.