If another similar service offered significantly more features or an otherwise better product I might be convinced to switch, but it would take a lot of convincing.
The other two products that come to mind as fitting in this category are Sublime Text and Balsamiq mockups. Both are great products, but are backed by even better companies / people.
In the offline world, I feel the same way about my (State Farm) insurance agent. His office has bent over backward when necessary to ensure things are taken care of.
Great customer service, honesty, and listening to the customer goes a long ways toward building a successful business. This is why Pinboard will thrive and profit while Delicious continues to sputter.
Not to be morbid, but using Pinboard is about as precarious a practice as using Magnolia was.
That rant about hosting already was a sign of trouble.
Pinboard rests on the shoulders of one developer, then the "hit by the bus" question becomes "hit by a tricycle" question.
How do you ensure longevity for a service like this?
Also didn't like running Net::Delicious and watching it fail.
Or watching my Firefox Delicious plugin completely fail after years of solid everyday use.
Unfortunately, my import into Pinboard left me with incomplete link history, but I assume the dev will help me figure out why it didn't like my entire feed.