This article is a comparison between Ubuntu 12.04 and Fedora 17 and has been divided into six sections.
Installation
Installation process in ubuntu 12.04 is a breeze with ease and Fedora's Anaconda installer is also very easy.
Desktop Environment
Ubuntu 12.04 features Unity as default interface which looks absolutely cool and the lightdm login manager is also very nice. On the other hand Fedora 17 has Gnome 3.4 which gives macish look and feel. Both Ubuntu and fedora also have KDE, XFCE and LXDE although in ubuntu KDE distribution is known as Kbuntu, XFCE distro as Xubuntu and LXDE as Lubuntu.
Usability
Ubuntu has a number of usability enhancements and is fairly easy to use the new HUD enables us to search through nested menus, files etc. the dash contains lenses which easily lets us to search through music, video and other content both locally and online. On the other hand fedora has vanilla gnome 3.4 and doesn't give attention to usability and therefore bit hard to use for newbies.
Software
Ubuntu contains decently updated software and the famous Ubuntu software centre and 'apt' . Ubuntu one is included which gives you 5gb of online space. You can choose to install and mp3 and other codecs at the time of installation. Ubuntu 12.04 is very stable. While on fedora the software is more updated than ubuntu but there is no software centre you have just plain add remove software the software can also be installed through 'yum'. There are a number of enterprise level tools such as jboss, openstack, boxes etc are included. Fedora 16 & 17 is rock solid stable. Fedora don't contains any mono packages and propietary softwares.
Support
Though both ubuntu and fedora are community distro but are backed by Cannonical and Red Hat respectively. Ubuntu nonLTS version such as 11.10, 11.04, 12.10 are supported for 18 months while LTS edition such as 12.04 will be supported for 5 years. Fedora is supported for 13 months and the community support is also good.
Conclusion
Ubuntu and fedora are both nice distribution and worth trying . Ubuntu is best for new users and those who want a system for a long go . While Fedora is best for who have intermediate knowledge of linux and those who live bleeding edge and try out new tools.