I'm increasingly impressed with the progress that OpenBSD is making. They're hitting some real problems on the head and actually letting us know what the changes are in a concise form as they always have.
Compare this to a Ubuntu LTS release which is virtually impossible to determine a detailed change list for past the marketing and UI changes.
I found this ~14 minute interview with Theo de Raadt from ruBSD very interesting and apropos OpenBSD's approach to trail-blazing "painful" changes: https://www.youtube.com/watch?v=OXS8ljif9b8
tl;dw: Changes that must be done, must be DONE. The only way to see the ACTUAL impact is to just do it already and get feedback from real users. When the dust has settled, less brave projects can follow suit. I'm donating.
I've been using it since 2.4 as well but the progress is remarkable considering the team size and funding. Progress for me is the replacement of non-BSD licensed parts and top notch re-engineering of the old rusty bits as well as hardware support which is pretty damn solid and reliable.
Compare this to a Ubuntu LTS release which is virtually impossible to determine a detailed change list for past the marketing and UI changes.