I have used NetBSD for years (2000-2005 timeframe), it is one of the cleanest UNIX systems that really sticks to the UNIX philosophy. Unfortunately, it never gained much traction, leading to a shortage of drivers, etc. In some ways it is surprising, you'd think that appliance vendors would love a good UNIX system under a liberal license.
This was exactly my feeling about NetBSD. FreeBSD was the fast BSD; OpenBSD was the secure BSD; and NetBSD was, well, never discussed in the terms I found most useful. People talked about it as the "ported to everything BSD," but what I remember most was its consistency and clearly thought out design.
Case in point, I remember when WiFi started becoming more prevalent. I can't even remember the hoops I had to jump through to get WiFi working in Linux. I just remember being annoyed that I couldn't configure the new network interface through ifconfig--I mean, it's a network interface! By contrast, I remember being pleasantly surprised at the lengths NetBSD had gone through to make WiFi a natural extension to the existing network configuration tools.
I ran NetBSD as my primary workstation OS for a few years 99-03 or thereabouts, and then on an assortment of other small systems, servers, and appliance-like things for somewhat longer. I even used the brilliant pkgsrc on FreeBSD, Linux, AIX, and MacOS X for a while. In the end, I gravitated away from NetBSD for the reasons you mentioned. It was never a quality problem, it was an inertia problem. Sad, because it really was a lovely system.
