XS still works for me in Poser 11. I basically use it in all scenes to mass-edit materials. I wonder why it doesn't work for you. I also have NetherWorks MAT Panel, though I don't use it as much as XS.
One of the things I like the most on ShaderWorks Advanced Material Manager is the ability of auto-selecting MAT zones that share the same shader settings, and/or texture maps. After we set our filtering options, when we select a MAT zone, it auto-selects all others that have the same settings. Once these zones are auto-checked to fit your criteria, editing one of them updates all the other automatically. If we disable maps, we can edit, for example, all skin MAT zones at once in a single pass, like changing the skin tone, specularity, and so on. Here again, editing one updates all. I find this a very smart way of doing things.
On XS, I like the ability of rewiring shader nodes from multiple MAT zones to different places. For example, I select all skin MAT zones, and rewire whatever is plugged to the bump to the specular channel, disconnect alternate diffuse, alternate specular, and change the diffuse color, change the bump value, all in one pass over all skin MAT zones at once. This is super easy and fast.
XS has loads of extra utilities, like remove all orphan nodes, reset MAT zones to a specific setting, change all texture maps in all channels by different ones in one pass, and so on. It's a single panel, and it does so much, and so well. It has become an essential part of my workflow.