Its not so much the reading. Its the slow page loading which gets me down. If people did pagination right with ajax preloading the next page then I would be happy. 99% of sites do not do this. Instead their sites are slow because they have to load a bunch of third party ad's. Moving from page to page when each page takes 2-3 seconds to load kills the reading experience.
A Wired article featured on HN recently. I don't remember what it was about but it had a gallery on it. You would think in today's day and age when you click the thumbnail the main image would change. On this wired story no.. the whole page reloaded. Due to third party ad's each page load took ages. The page didn't bounce down to where the image should show. While I thought the topic was interesting the user experience was so terrible I abandoned it.
If you are going to force pagination on readers then have a single page option. Preferably at the top of the article. This way you cater for everyone.