DesktopLinux have had a look at the specification and announcement of Beta4 of SimplyMEPIS. No hands-on, though.
Read a bit more about Beta 4 here
Analysis — The MEPIS project has released the fourth beta release of version 6.0 of its KDE- and Ubuntu-based SimplyMEPIS-32 and SimplyMEPIS-64 Linux distributions. Beta 4 introduces the 2.6.17-20 kernel, WiFi support improvements, and the ability to run MEPIS live from a USB key.