We have been using these nifty converters on several installations, all running on Win98/ME, without any problems.
Recently we had to "upgrade" one of these systems to XP PE. Even using new XP drivers provided by the manufacturers, we can't get the damn things to operate stable: sudden problems with pointer device (tried all possible types now without good results), Bill's good-old "blue screen" and similar surprises, so we had to move back to PCI type ports to get the thing stable again. Although it is 99% sure to be caused by driver conflicts, I just warn you ...