The main problems in su2mxs v1 are related to the ”beta style” material setup. That is the same problem as in RC5. On the other hand you can now link directly to mxm materials, and access the material editor from SU.
With Hrothgars SketchRender script you can now improve your workflow dramatically. You can now link materials in the SU materials library to mxm materials, and those linked materials are assigned semi-automatically (by select all, Assign Materials). It still has some limitations (only works properly with one SU folder, and all selected faces should have linked materials), but I am sure Hrothgar can solve these issues with some encouragement from the community here

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Since I started using only linked mxm materials I haven’t had the “black faces” problem.
I would recommend updating to v1.0.
I believe there is a new improved version under construction, but I don’t know when it will be available.
Sheik