My opinion is CDex is one of the few better programs of the type. The only real competition to it would be Exact Audio Copy (free/cardware), Feurio! (Shareware) and Plextools (Plextor drives only). Of these group of programs, Exact Audio Copy and Plextor have the superior secure mode extraction modes.
It's one of only a few CD "rippers" with secure mode extraction which means during extraction it will do error detection and correction, instead of just "Burst mode" which most other similar programs use regardless of their price. Secure mode significantly helps guard against skips, chirps or misc other reading errors. I've been able to copy heavily scratched CDs perfectly with secure mode extraction, though depending on your drive or CD damage your mileage may very. Read-in and Read-out Offsets can also be configured. It's comes with LAME MP3 encoder which is capable of providing higher quality MP3 encodes than that of Xing (no short block support no Mid-Side joint stereo used in Audio Catalyst & RealOne), Blade (no joint stereo mode, poorly tuned psymodel) or fastenc (often has the stereo collapse bug with JS in High Quality mode - used in MusicMatch Jukebox). Pretty much any commanline encoder can be used with CDex meaning one could encode using MusePack (MPC), Psytel aacenc/fastenc (AAC), FAAC (AAC), FLAC, Shorten (SHN) or any custom version of LAME or Vorbis.
It's pretty easy to use given you have some encoding knowledge. It's highly recommended that you spend some time configuring it properly, but guides such as this make it a no-brainer: http://cdexos.sourceforge.net/boards/index.php?act=ST&f=12&t=849&s=8188e03c7c15ab5e25071bb07e57ad97