We currently have an HP DL server with two NICs. Because on Windows Server 2008 Network teaming requires OEM software (which we have but not configured for it) we just have two IPs on physical and two virtual network adapters in each VM we run for Geekzone, monitoring and other servers.
The idea is to load balance, but obviously there's no automatic failover like the one NIC Teaming would provide (not without manually changing DNS, then disabling NIC, etc).
From observation in the last month since we enabled the second NIC it seems performance has been marginally better and traffic seems equally balanced between IP addresses.
Apart from the obvious automatic failover/resiliency of NIC teaming, is anyone using it and seeing better performance than just two NICs with two IP addresses?