Bering-uClibc 5.x is basically Bering-uClibc 4.x brought up to date with the latest versions of the main software components and with reworked toolchain. In particular:
Toolchain is reworked to support 'true' cross-compilation gcc has been updated to 4.6.3. The Linux kernel has been upgraded from 2.6.35 to 3.4.x (current 4.0 version uses longterm 2.6.35 kernel branch). The uClibc library is upgraded from 0.9.30 to 0.9.32.
The main advantages are:
Kernel-mode PPTP/L2TP/PPPoE server (accel-ppp) which is 'all-in-one' powerful BRAS daemon with shaper like BSD's mpd. Possibility to build binaries for any target platform which supports Linux