Ubuntu 15.10 Alpha 2 was released today for Kubuntu, Lubuntu, Xubuntu, Ubuntu MATE and Ubuntu Kylin! After testing for the day on a live DVD I haven’t found any major bugs. The one change that I can see from 15.04 to 15.10 is the removal of AbiWord and Gimp. Alpha 2 is running version 4.12 of XFCE. Firefox is still on version 38. Only once so far my computer has crashed and that was when playing music in Chrome on Pandora and configuring a network at the same time.
You can get the latest nightly builds at http://cdimage.ubuntu.com/daily-live/current/