It took me four years to getting around to hearing it. I always liked Bowie's work in the seventies, but I was less thrilled with what came after, and 1983's Let's Dance was my last purchase, and that one got purged from the stacks a long time ago. I recently read The Age of Bowie by Paul Morley (I can't recommend the book), and that got me into going back to the music I was less familiar with from the 90s and 2000s, and brought me to Blackstar. I was pleasantly surprised by some of his more recent music, but Blackstar just blew me away.
It is not jazz, but it is played by a talented jazz band. It doesn't rock very much, but there are some rock moments. The band deserve extra credit. The songs are unusually strong. It has a unified sound, more so to my ears than anything he'd done in 20 years. If you have any interest in Bowie, you really should hear it. And maybe especially if, like me, you wouldn't be expecting anything great from David Bowie. I would put this in my list of the top 5 best David Bowie records. It's that good.
It is no surprise that David Bowie had one more trick up his sleeve, but one so magnificent is just remarkable.