This product is meant to replace Oracle's Data Guard replication. The setup is simple and it can handle bi directional replication very easily. Training cost is minimal and most DBAs self learn this product. replication between various types of databases is supported and software foot print is very small . Change trails are not very big and easy to manage and store.
Room for Improvement:
DDL (data definition language) replication is still to mature and can be an issue. Supplemental logging causes extra redo log generation in the log storage. Licensing cost is higher as compared to other replication products. Configuration of Golden Gate in HA (High Availability) mode needs setup of extra VIPs which can be challenging in a RAC environment.
Integration of Golden Gate with monitoring tools like OEM (Oracle Enterprise Manager) is still not available and most DBAs monitor this with custom scripts. We chose this product mostly on it's bidirectional replication feature and easy setup. Some applications are using this as a messaging mechanism between multiple databases.