I installed NetBSD 3.1 sometime ago. I also used the pkgsrc binary CD to install GNOME so that I had a basic working installation.
One of the annoying 'feature' of NetBSD 3.1 is that it is not compliant to multi-boot so that grub will not be able to pass the kernel parameters to it. Therefore I need to answer several questions before I can boot into NetBSD. Somehow pkg_add did not work well with ftp.netbsd.org.
So now NetBSD 4.0 is just out. So I update the existing installation to it today. It is a very smooth process. More importantly, it is compatible with multiboot and grub has no problem to boot NetBSD 4.0 now. The existing 3.1 binary packages are still working. pkg_add is now working as well with ftp.netbsd.org even though it still prints out some error messages.
Since I have got PICkit 2 to work under FreeBSD (with HPS USB stack), I will try to get it to work under NetBSD. But I have never used NetBSD before, this might take some time.