Whether you know it or not, this has the potential of becoming a "wild" thread! I will therefore attempt to tread lightly...
The answer to your question will be predicated on a number of things. What system do you presently use? Do you already have experience with video editing apps, or are you starting from scratch? How "high tech" are you intending to go, or more importantly, how serious are you about your editing? There are numerous other factors to be addressed as well.
At the low end, iMovie on the Mac is an acceptable solution for many amateurs. There are also a number of low cost apps for the PC which are a bit more powerful, but with a bit steeper learning curve.
At the mid range, there are solutions from Adobe (Premier Pro), Avid (Avid Xpress) and Apple (Final Cut Pro). Adobe is PC only, Apple is Mac only, and Avid is cross platform.
At the High end, it is all about budget.
Apple's Final Cut Pro system can be upgraded to a hardware I/O based system, taking it up to the $30K price point with much better compression and real time performance. Avid is the leader here with hardware based solutions costing up to $125K. Adobe does not really have an entry in this arena, at least not one that compares (in my mind, at least).
Proffesionaly, I have 5 Avid Media Composer systems on a shared media system called Unity. Due to cost restrains, upgrade requirements, etc, I will very likely be replacing my systems with Apple Final Cut Studio and the X-San system early next year.
The editors here are not overly unhappy with this solution as the newest offerings from Avid are much more "tuned" on the PC, and we are sticking with a Mac solution, as our editors are all Mac users.
In summation, pick a platform you are comfortable with, and an excellent solution at ANY price point is available. The Mac vs. PC wars I see in response to these types of questions are stupid. There are no "REAL" advantages to either system in the long run.
HTH
btw, my official title is Director of Technology, Warner Bros. Idea Place. Not that my opinions have any extra credence. I just mention it so you understand why I lean towards the "higher dollar" solutions for my enterprise systems.