I have both but i use facebook more than myspace cuz all of my friends uses it. its a great website for networking. before facebook I didn't have much contact with my relatives (cousins, aunts uncle etc) but now I have almost all of them ( I have like over 40 cousins so i dont have them all yet lol)
as for the name thing you dot have to put ur full name in you can just make up a name and last name but its makes it harder for people who may have known you from years ago to find you. many ppl just put first name and first letter of last name.
as for the contact thing, people dont just add you, they have to have your permission to let them add you. so if you dont know them dont add them its that simple. although you can set it to automaticly let other ppl add you, but not alot of ppl have that set up for their profile.
simple said i love facebook period!