I use infinite scroll on my blog (http://alex.clst.org/dbd) and though I generally enjoy all the features of Jetpack have one annoyance with the infinite scroll module:
Say a visitor to the front page of my blog scrolls down to a earlier page of posts and then clicks on one of the posts to read it in detail and/or leave a comment. When they go back to the previous page that page is now the page they'd scrolled to, but not with an ability to scroll back to the top/front page of the blog. Is there a way, or is it a feature being worked on, to make the back button behavior when returning to a infinitely scrollable "page" load the top/main page and then scroll to the position they were previously at? Aside from this minor annoyance infinite scroll os a great addition to any blog that uses Jetpack.