I watched this movie, hoping it would recall my memories of Free before I started the 3rd season. It didn't really work, because it recapped the 2nd season and skipped over the 1st season. What I did then was read Wikipedia summaries. Actually I should've just read all the summaries and jumped right into season 3. Yeah, that was a whole 1h30min gone. For the extra scenes, the other reviewers have commented on them. I forgot 90% of what happens in the original series so I don't really know which ones were the extra scenes and how significant they were.
Overall the movie was pretty warm and fuzzy. I don't know how well it stands on its own but it felt very complete. It's just a simple story of the swim club swimming in the tournament and also a coming-of-age story, basically the second season condensed. The movie didn't really help me with my initial goal of recaps but I liked it, if not just for the new Style Five songs.