I installed it on a spare partition.
Summary:
installer:
still no "don't install grub" option
Canonical still isn't interested in what do you want to install on the computer
shortly: nothing changed
startup:
amazingly fast; it's even faster than shutdown
stability:
well, I know this is a beta... but it's the most buggy beta I've ever seen. Synaptic crashed 3 times, user setup didn't start at all. I was continously getting messages about mysterious kernel errors, Firefox threw exceptions on every close. If they really want a "bugless" OS (as they declared), they should hurry a bit (deadline is 29. April)
hw:
64-bit version, without any application running, ate about 700 MB RAM. In comparison, my Salix with Opera running is about 440 MB, my old Slackware with LXDE sometimes went down to 200 MB and even Ubuntu 9.04 needed just 450 MB. This may be because of the new Gnome and because compiz became the primary wm.
look&feel:
this edition is extremely ugly. The background is purple the icons are orange and the window borders are black (and the buttons somewhy had been put on the left).
other:
there's a new (?) system tool called "computer janitor". It's used to keep the system clean. Unfortunately, I couldn't try it, because there aren't enough packages to make a really big mess yet
a movie editor is included in the installation
the sound system is good, I've some files which are very quiet under Salix
suspend & wakeup is very slow
In conclusion:
I'm not familiar with the development procedure of Ubuntu, but I think a system should be more mature less than a month before release(, however boot is really lightning fast)