Netperf is probably the most widely adopted network benchmark out there. Almost every company I've seen has used it for performance and Q/A testing. For what it does, it is quite efficient. I remember when I was doing 10GbE drivers in the mid 2000s, people would complain of terrible performance on "modern" tools like iperf, but would see 10Gb/s using netperf. This is because "modern" tools did things like gettimeofday() around every socket read or write, making them basically gettomeofday() benchmarks at high message rates, but netperf did the gettimeofday() around the entire test.
Netperf's problem has always been that it is single connection, single-threaded. Most people use it coupled with patches or scripts to run many copies of netperf in parallel.
I suspect what happened in these tests is that the author just ran a single copy of the tests, and did not bother to adjust the interrupt coalesing settings. So what he really measured was different interrupt coalescing settings in the FreeBSD and Linux driver. If he'd have run 500 or 1000 copies, I'll bet he'd see vastly different results.
BTW, if you're looking for a modern network benchmark, check out uperf (http://uperf.org/) It seems to have been largely abandoned after the Oracle acquisition, which is a shame, because it was just plane awesome. It could replicate many scenarios very realistically, supported multi-threading, etc.