The idea is quite simple, similar to Instapaper and the like. In fact, Google's own Chrome to Phone functionality has much the same concept: you're reading something in your computer's web browser, want to finish it on your phone, so you hit a button and up it pops on your handset. But, Read it Later Pro is rather more comprehensive than that. Naturally you can save links to read later, but the app will proactively download text and images so that you can read that content on a plane in the sky or a train in a tunnel.
On the app you're presented with options for whether text and images or only text should be downloaded, or indeed anything at all if you have complete and total faith in your data connection. You can also choose whether the integrated browser identifies itself as mobile or desktop -- handy for those who like scrolling. Sadly we couldn't get videos and other Flash content to show up within the app, but that's not much of a surprise given the app is called Read it Later, not Watch it Later.
There are plug-ins and smart bookmarks that can be added to just about every desktop browser in existence, making it just a click or two for you to add content to your list. On Android, Read it Later is added to the Share menu, meaning you can quickly add content from your mobile browser or a bunch of other apps. Once added we found it takes around five to 10 seconds for a new link to show up in the app itself, and perhaps that long again to download the content depending on the article size. You can also apply tags to entries for filtering purposes, and naturally mark them as read to clear them out.
Ultimately it's a handy app. The default "article view" does a good job of simplifying content for readability on smaller screens, and that you can send as many things as you like and read them whenever you like is certainly nice. Ground-breaking revolution in mobile reading? Nah. Worth .99? Sure -- if you like reading things.