Better is in the ear of the beholder!
We did a compairision of an Ayre to the Edge and no contest the Edge was the favorite. The Ayre amplifiers are very clean but tend to sound a bit sterile to me. The Edge was warmer, with a wider and deeper soundstage.
I have never heard the Kharma nor Pass in my system so I can not guess on that one.
The Kharma amplifiers are Hypex based which is certaintly respectable Class D. We just got in the Nuforce V2 versions which are remarkable amplifiers for the price but with a totally different presentation to the Edge.