Comment 29 for bug 564072

Thibault - sort of. The main reason that the image quality is worse is that LCD panels just dont look much good at anything other than their native resolution, even on Windows or OS X. The difference in DPI is probably only one of the intermediate factors involved.

The good news is that Unity 7 on Ubuntu 14.04 "Trusty Tahr" will have support for HiDPI displays. Additionally, Ubuntu developers are planning HiDPI support for the Ubuntu Linux boot experience - when dealing with GRUB2's boot-loader menu and the Plymouth boot splash screen. They are also investigating HiDPI support for Linux virtual consoles. Specifically, "Developers at this week's vUDS session will be working on a 2x version of the GRUB2 font for basic HiDPI support by just appearing twice as big, working on GRUB2 support for returning a display's physical dimensions, work out support for a scaling factor within Ubuntu's Plymouth theme, and support for a scaling factor within the console-setup font configuration."

There is also bug #1292218 which is described as "The lockscreen has correct Panel HiDPI support, but the prompt doesn't scale right now."

Some of this additional work might be ready for Ubuntu 14.04 "Trusty Tahr" but it is unlikely that all of the HiDPI improvements will be ready for that release.