Replicating spatial data was one of the reasons why we (USDA Forest Service) chose GoldenGate. We too are on 11g and we are using ArcGIS tools with SDO geometry mostly and some SDE.
We recently ran into problem with replicating versioned feature class: adds were getting discarded. Problem turned out to be with our TEMP_GIS tablespace: it did not have any datafiles assigned to it in our target/replica database.
I may sound like a spatial veteran with these comments, but I am a spatial beginner indeed. I would be glad to share our experiences