I'm using it occasionally with Vista and I can't remind having run into trouble - but then, I normally just write the geo tags just once with GeoSetter, then do the further keywording etc... in Lightroom.
Actually, I normally geotag from GPS traces (in GPX format) when ingesting with ImageIngester Pro. I only use Geosetter when I don't have a GPX trace at hand, because it is incredibly easy to use to geoset "manually" on a Google map. Also, one of the GPS devices I use doesn't provide altitude information in the GPX, and here also Geosetter comes in handy to quickly look up a bunch of coordinates and pull the altitude in the EXIFs.
Jean-FranÃ§ois (JF in shortÂ