I'm looking for some real world numbers for comparison. If anyone would like to contribute, I'd like to see version of NetFlow, average and peak flows/sec, estimated traffic combined for all interfaces sending flows, and, if possible, any extra configuration at the source end (i.e., sampling).
v5, ~15k flows/sec average, ~65k flows/sec peak, ~400Mbps combined over 2 interfaces (bidirectional), no extra config.