In broad terms, antiX M7.2 is a community-driven project to combine a Mepis 7.2 base (kernel is 2.6.22-1-mepis-smp) with the vast Debian package repositories and the Fluxbox and IceWM window managers.
Read it here
Would I recommend antiX?
Yes, but only for experienced Lxers: It's simply not suitable for Linux newbies, given the slightly esoteric nature of the WMs and the pared-down desktops (newbies do like their icons, don't they!).
If you've been around the Linux block a few times and are looking for a project, possibly using an old piece of hardware, then antiX is a marvellous choice.