In the early 2000's, I had to set up a dedicated CVS server for my 10-person startup. I was the dual hat "dev & admin" guy. We were small, but had good desktop machines with good SCSI disks in them (top of the line Seagate, if I remember right).
I set up both a Linux and a FreeBSD dedicated CVS server. We were all happy to try one server for a day, copy the repo to the other one for a day, and try things out.
Well, FreeBSD was a bitch to set up compared to Linux and was easily 10X slower in every way measurable. Like, "cvs up" would take 5 seconds from the Linux server compared to a minute on FreeBSD (yes, same repo...). Hopping on to the FreeBSD box locally showed that every kind of disk activity was way slower than Linux.
I went to the FreeBSD newsgroups and got laughed at. Not a single piece of helpful info. I did get several large words thrown at me about how I didn't understand the benchmarks and the performance shouldn't be noticeable to the end users. At least one guy took to emailing me directly about how I shouldn't be comparing Linux to FreeBSD.
After 2 or 3 days of wrestling, I powered off the FreeBSD box, installed Linux on it, and never considered FreeBSD again.