instacss.com or dochub.io will take you to the same place, so it doesn't matter which one you bookmark. We moved the domain just to make the purpose of the site clearer moving forward.
As for the long initial load time, client-side caching is on the top of our list of todos, so stay tuned (or just wait for the HN effect to wear off :)).
It's not just the HN effect. I used instacss.com yesterday to look up the allowed values for -webkit-user-select and was rather surprised at how long it took before the page was usable. That said, the site really is brilliant.
As for the long initial load time, client-side caching is on the top of our list of todos, so stay tuned (or just wait for the HN effect to wear off :)).