I agree with that comment, which was one of the reasons rtc.io was created in the first place. A lot of the other libraries hide away the core browser objects through higher-level JS objects, whereas the core rtc.io library (rtc - https://github.com/rtc-io/rtc) encourages direct use of the browser api.

Some of the other modules (rtc-quickconnect, rtc-glue, etc) in the rtc.io suite, however, do take you further away from the metal but if you are comfortable with the core browser APIs then using a combination of rtc-signaller and the connection coupling helper in rtc (https://github.com/rtc-io/rtc/blob/master/couple.js) will probably give the most flexible option for writing a WebRTC application.

Just be aware that there are some bizarre edge cases when working with WebRTC that can leave you scratching your head at times. The rtc/couple module takes care of some, but there are still others that I'm still investigating solutions for, e.g. https://github.com/rtc-io/rtc/issues/14