Some current problems,
which might affect you (I am heavily working on it):

- pass only matrices with number type polynomial back to Singular

- a Ring change with r.set() doesn't work properly at the moment, so don't do it

- LIB loading is equivalent to LIB("dgsjkgjs") and not LIB "djksdgsjkdjks"
 the former fails generally in Singular, so load your libs, before you go to python

- Although it would be quite analogous, there exists currently no possibility of accessing local Singular variables

- don't use polynomial(<string>) this is only in for testing purposes and does only work for monomials