A package universe is better than Monticello or SqueakMap for beginners and for people who don't care whether they have the absolute latest version, but just want something that is going to work.
Squeak Map is better for people who want to explore, for people who want to find everything, even if it takes a little work to get it going.
Monticello is better for people who want to participate in the development of a package or who want the latest version. It takes more expertise to use Monticello than to use a package universe.
A package universe comes with some sort of understanding (I was going to say "guarentee", but changed my mind) that the packages all work together. This implies that someone is responsible for it. Squeak Map is a set of things that someone, at some time, thought was interesting, but many of them do not work together, and that is OK. It would not be OK if a package universe contained packages that did not work together. I think a package universe will work best if it is "owned" by someone or by a small group. A package universe is by design not complete, but it is consistent.
Squeak Map is complete. There is only one Squeak Map, and everything is in it. Or should be. Anybody can write to it, and anybody who has ever made a Squeak package should write to it to tell the world about what they have done. Consequently, Squeak Map is not consistent.
So, I think there is room for all three systems. They each do something different.
I think that newcomers should start out with a package universe and then graduate to Squeak Map and Monticello.
-Ralph Johnson