Folks with mod points should bump this (AC) parent up; it's pretty much spot-on.
Here are a few extra data points...
I've been following the NetBSD 5.0 branch since it turned -RC on sparc, i386 and ARM. It's a significant step forward in a lot of ways. For example, on my EEE PC 900, everything works... something not every Linux distro has managed to do.
In NetBSD, there seems to be a stronger realization that developer time is precious. For example, NetBSD suffers a lot less from 'superfluous redesign' than Linux. Many years ago, I wrote a few Linux 2.0 device drivers for a few ISA and PCI data acquisition boards I was using. I had to make fairly significant changes for kernel 2.2, then 2.4, then 2.6. And since then... don't get me started. I've had to fix inane code breakages in the 2.6 series several times. In NetBSD, my driver code didn't need to evolve a tenth as much. Code interfaces are just more stable.
Just the build system alone is a huge time saver on embedded systems. You don't have to go searching around for cross-compilers, toolchains and all the other things that can be painful in Linux (unless your vendor spent a lot of time to assemble them for you). In NetBSD, this stuff is all built right into the base system to begin with.
Admittedly, on the desktop, NetBSD is still more work than it should be, even compared to typical Linux distros. It's about like the other BSDs, and not so different from a basic Debian install, for example. There's a growing realization in the NetBSD community that 'making it easier' to get a functional modern desktop environment running is worthwhile. Hopefully this gains traction.
NetBSD is a really nice system, which undeservedly gets overlooked a lot. It's definitely worth a look.