Pros

• It works with any language. If it can request http urls, it works
• All the data is returned as String. No bizarre data-type conversions needed
• Support for simple response based on field separators or XML response
• As you query a webservice in a webserver, you can install this webserver in another server, and so having a more split architecture, connect to different clusters in remote locations, etc… Layers. It works as proxy

Cons

• As you query a webservice in a webserver is not as fast as a fully native driver. The main time is spent connecting to the cluster. Average queries take 0.1 seconds in our workstation
• You may have some limit in GET requests length (default in apache is 8190 bytes, and can be increased via LimitRequestLine directive)