I just updated to the latest beta release of Ubuntu, codenamed Quantal Quetzel (or, as I call it, Quantum Pretzel), on my Lenovo x120e netbook.
Installation went smoothly and my optional broadcom wireless chipset was detected and enabled automatically during installation. This is the first time that has loaded without any hassle on my part, and I'm very pleased with the result. Users with the default atheros chipset have been enjoying this ease of installation for several releases already.
Installation went smoothly, now that they've squashed a particularly nasty bug in the installer that would crash if you tried to manually modify the partition table...
Once I booted into the actual installed system, it defaulted to use the open source driver for my integrated Radeon Fusion chipset, which provides adequate acceleration for transparency and other desktop composition goodies. Speaking of, the default Unity interface seems to have been improved further beyond the already much-improved Precise release, with the icons in the dock being smaller and less cartoony on my machine, with transparent backgrounds rather than the garish multicolored backgrounds from before (YMMV).
Virtual desktop switching also seems much improved. I never used it before because it felt clunky and laggy, but now transitions are smooth and dragging windows among desktops is effortless and intuitive. However, sometimes the windowing system gets confused and tries to maximize things inappropriately, leaving a transparent orange overlay on the screen--to show where it's trying to maximize--until you click on the window decoration and let it do its thing, then resize.
Suspend works well on this machine, faster than before and with quicker wakeups, and the wireless reconnects faster after suspend, as well. There doesn't seem to be a hibernate option anymore, so I couldn't test that.
One problem I ran into: I previously used my /etc/fstab to mount a shared folder from my network at startup via smbfs, but that package has been removed upstream, so now I use cifs as the filesystem and that seems to work just fine.
If you have any questions or anything you'd like me to test, feel free to hit me up in the comments.