I was a Barbour International user in the late '70s, when these did out perform the nylon equivalents available at the time. But it was sticky and got dirty when it was warm & set like concrete when it got cold, had very little in the way of warmth & probably didn't offer much in the way of protection. Labour intensive & messy to keep it well enough waxed to be mostly water repellant as well. When it was well worn it was sold to a workmate who wanted such a worn-out jacket to make it appear that he was a "well hard biker".
I have a lower cost Trailmaster / International copy I got when I had my first Bullet & it made a comfortable summer jacket. The genuine Belstaff & Barbour versions are silly "fashion item" prices now, but there are various alternatives available here at more "sensible" levels. Still dirty & a bit wiffy, though, and it hasn't been out of the wardrobe for a good few years now as it could do with re-waxing....