iComic viewer application was substantially the same characteristics as ComicZeal4, perhaps a little less advanced, but for "price", who would complain? iComic Reader can read files of type CBR, CBZ, ZIP and RAR.
Sending files in the application does is unfortunately not as simple as ComicZeal 4. Several ways are possible and very well explained on the page of the iTunes application, such as sending via FTP.
However, if you have an account DropBox, the handling is really much simpler:
iComic Reader is available in paid version without advertising. And works also on iPad.