i dont care bout the price , size , mp or zoom , etc..... my main concern is IMAGE QUALITY
Of the things you mention mp (I assume you mean megapixels) is definitely a factor in image quality. I also assume that with image quality you do not mean the composing capabilities of the camera (If you do consider that part of the image quality then also optical zoom IS a factor).
As I do not have experience with any of the mentioned cams I will just restrict myself to these observations. However I do suggest you look into the reviews posted on www.dpreview.com
as these will get into the image quality aspects quite thoroughly. The sony's have not been reviewed by dpreview. The Canon is there, though. The Casio EX-Z4 has not been reviewed (yet) but dpreview has some info on it, and there is an extensive review of the EX-Z3 (and if MP is not important, it is basically the same cam, note though the comment that Phil Askey made on that).
Steve's site (this one) carries more reviews (the sony's are covered for instance) but these go into less detail with regard to image quality.