Don't know anything about the Gerber but I have both the P4 and S4 models.  I like the S4 a bit more than the P4 for everyday carry.  I also carry a LM Wave in my daypack so I don't need the small pliers.  The scissors works a LOT better than the Fiskar type scissors found on most other type of multi-tools.  Comes in handy for trimming moustaches and is quite useable as a nail trimmer.