COBRAHQ  I had been searching for a way to merge my foreign films, and anime subtitles for months now... nothing was easy, and everything involved either running windows on my macbook pro or some long damn process. I found this app through some forum discussions after doing a google search... downloaded the demo, tried it once... bought it instantly.

Simple to use and does a damn good job on the merge (with a good chunk of options).  
(Version 1.2.2)