Cool! It looks to me like most of those approaches are a lot more sophisticated and work even when the text doesn't have any time annotations. At a first glance

Cool! It looks to me like most of those approaches are a lot more sophisticated and work even when the text doesn't have any time annotations. At a first glance, it looks like the major downside is that these approaches are geared toward particular target languages. Subsync's advantage is its simplicity: by limiting the acoustic analysis part to simple voice detection, it can perform alignment between subtitles and audio/video in different languages, which is great for when you want to watch a TV episode in another language, but your video includes the previous episode's recap and your subtitles do not (or vice-versa). I'll definitely be taking a deeper look at these to see if there's any ideas / functionality that can be further incorporated.