The main problem with NetBSD is that is lacks a leader and clear goals. In the failed attempt of making everyone happy, it's stuck in a limbo: just think about the fact it still uses CVS in order to satisfy the few devs still willing to carry out their own projects on it, when subversion would be a much more rational choice in 2018. The official goal is portability and legacy hardware, but this is such a vague objective that there's still confusion on which archs to keep maintaining. The power to make decision is split between 2 teams, the core and the board. The board should take care of the administrative aspect and the fund-raising campaign, de facto it always "interjects" in the core's decisions preventing core to make innovations (I' actually quite against the board).
In a endless battle for survival where it gets less money than how much it spends per year, while wrong decisions and fate brought it from being arguably the leading Unix-like OS anyone would refer to as an example to the most niche and underrated project on earth, NetBSD still manages to surprises users like me. It's a very, very clean and polished OS, extremely lightweight, quite secure, with its own Xorg built-in patched version (like OpenBSd's Xenocara), and awesome firewall (NPF), tons of amazing utilities for system management and networking in base system (including the famous rump kernels) which I really would like to see adopted in other BSDs, and whcih make it a perfect router/firewall server, aside from a great development environment. A damn buggy hateful package system (pkgsrc), which is, on the other hand, actually really lightweight, smart-thought and portable, and you can't help but end up loving it, to the point I've used it on OpenIndiana, macOS and Slackware too. NetBSD it's just perfect for legacy hardware, niche archs and embedded, if you have an old laptop or a Rpi, just throw NetBSD on it and it's granted to be faster than anything else. The relatively good Xen port (which used to be better and it's quickly becoming outdated), wine, and the dosemu2 ports are other good pros for using it. NASA used NetBSD as base for its software run on space station in order to test and handle satellite networks
Personally I use the current branch (8.99), as it brings a lot of advantages (sndio, autofs, synaptics, the in-kernel audio mixer, metdown/spectre patches, KASLR, SMAP) over formal (which was 7.1.2 until a couple of days ago), and grants me access to the pkgsrc/wip repo, that contains a lot of software I like, including qTox, newsboat, qutebrowser, the OpenBSD's CWM version....