Is the pinboard.in reliable in terms of speed and uptime?

Stats in the DB show that the site has been fast (user page loads in about a quarter second) pretty much since launch. This is not due to developer skill; rather, the signup fee has kept the user base small enough to guarantee good performance, which is part of the idea.

As for uptime, we've had about 20 minutes of downtime this month, in order to set up a master/slave and enable SSL. I can't guarantee the happy streak will continue, but again the gatekeeping fee deters any massive spikes in load, spam, and other growing pains that could take down the site.