It's not necessarily a choice of "Pinboard" vs. "Microsoft" vs. "create your own bookmarking website."
For me, it's "Pinboard" vs. "text file". At $11/year, I would choose Pinboard any time. I've been a subscriber for years and I don't expect anything for free. But at $22/year, I'll go with the text file.
I was going to correct you on pricing because I did a one-time payment of about $11 back in 2010. It used to be that there was a one-time price that incremented as people signed up. So really early people could have paid a dollar or so, I guess.
But it's now a yearly fee. Which is good for us grandfathered people, since it means the service will stay around.