I think that the package system , no matter it is deb or rpm , is good for open source system. It has minimized the space required , and it can get software easily.

Setup an new Ubuntu system is a pretty simple task , whatever you found that a software is not installed , you can open synaptic and search for the download. You won't need to find it from Google, from different site.

However, it has its disadvantage , you can not enjoy the newest software , you need to wait until the package manager is free to pack the software for you. For example , Firefox , you may need to wait for few days to weeks for newest version.

But I don't like windows installer , I think mac's dmg is more flexible solution of software installation. And such solution is already available on Linux:

http://www.elementary-project.com/wi...itle=AppImages