Ubuntu Jaunty 9.04 vs Fedora 11 - alphas screenshots comparison
Ubuntu 9.04 and Fedora 11 are in alpha stage, both use GNOME 2.26 in development, but some new feature (and regression) are already visible.
Kernel

Fedora uses a new system to report Kernel failures

Ubuntu: 2.6.28-6
Fedora: 2.6.29
Notes: My Attansic Gigabit Ethernet worked in Ubuntu Intrepid but not in Jaunty :( No problem with Fedora
ubuntu@ubuntu:~$ sudo ifconfig eth0 192.168.1.2 netmask 255.255.255.0 SIOCSIFADDR: No buffer space available SIOCSIFNETMASK: Cannot assign requested address ubuntu@ubuntu:~$ uname -a Linux ubuntu 2.6.28-6-generic #17-Ubuntu SMP Fri Jan 30 15:34:36 UTC 2009 i686 GNU/Linux
Audio

There is a gui to manage Pulsaudio instances

The Mic volume works in realtime

Ubuntu has too many audio volume tools
Web Browser

Fedora uses Firefox 3.1 with Gecko 1.9 and the OGG video support.
Ubuntu has still Firefox 3.0.x
Graphics and resolution

Ubuntu doesn't recornize my Dell 16:9 monitor
Package Kit

Package Kit install tool is lovely and it works.
Conclusion
There is no conclusion, both are alpha releases. However Ubuntu still didn't import the new cool features like the new GDM or themes but some regressions happen.
There is a new notification dialog but it isn't so exciting for a new release.
Fedora seems more innovative and stable than Ubuntu (Firefox 3.1, ext4, btrfs,..) but I got problems with NTFS Partitions and Flash, Mp3, Codecs,.. are still harder to install than in Ubuntu.