Oracle recommends bonding NET1 and NET2 together for redundancy purposes but will adding a third NIC aka NET3 result in better performance or will it merely result in triple redundancy for the Client Access Network? TIA for responses.
Under the default configuration, it would only provide a second backup connection. The default configuration on Exadata is to use "mode 1" bonds, or active/passive bonding. You are more than welcome to modify the client network to use LACP, but you need to ensure that your switches support whatever method of link aggregation you choose. Using mode 1 is the simplest of methods, and works without any requirements from the switch.