Facebook or MySpace?

How many people have wondered which social networking website they should use? 
Of all the choices, MySpace, Facebook, Bebo,
and so many others.  Yet, with all of the competition, the majority are at either MySpace
or Facebook.  Well, which one should be your main account? 
Some people (like myself) create multiple accounts on nearly every network just for the sake of staying
connected to your friends.  So, why are these two networks so popular?

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MySpace

Facebook

Fully Customizable Layout Can Only Customize the placement of the
applications Discernable and Unorganized UI across multiple
profiles. Standard, Clean, easy to navigate user interface
(Beta) Applications A large library of applications that can interact with
the user's profile or computer Fully Public Profiles
Profile's blocked off of visibility by network or friends added
Meta Networking Support Full-Fledged Networking embedded
MySpace TV Facebook's small video app
Large Ads Everywhere Small, generally un-obtrusive ads.

All in all (in my opinion anyway) Facebook is a lot more organized and
a lot easier to use (once you get the hang of it).  Maybe this is why it had a growth of 102% when
MySpace only grew 2?