im afraid ill have to disagree. not everything open source is always better. in the case of mirc i can definately see alot of builds with "less than honorable" purposes being passed as an authentic build.
next the issue of multiple developers. in some cases this can be good especially when the developers collaborate on the project but when they dont problems can arise. you download a build from someone whos only marginal and the build has more problems than the original one.
As a developer I would definately like to take a peek inside mIRC myself however i would never use any build that didnt come from khaled.