Justice League vs. Teen Titans is the latest direct to video release from the DC Animated Universe in the continuity established by Justice League: War (2015). I think this chapter could be completely skipped, but if you are a fan of this continuity, wait for its release on Netflix.
Starting with the title: First of all, it is misleading because it is a Teen Titans movie, not Justice League - Justice League members only have a ceremonial cameo. And I seriously hope this is the last time that we see "vs." in the title of a release from DC (after Batman vs. Robin and then Batman v Superman). Another point just before delving into the story line: I am kinda tired of the character designs (by Phil Bourassa). We need a new look - that is exactly why we see so many different art styles in the comics.
As for the story: the two main characters of the movie are Robin and Raven. Robin is sent to Summer camp so that he would behave a little better, and Raven is on the run from her inter-dimensional demon dad, Trigon! I don't know if we see much character development for Robin, but Raven is in for big changes. She has to open up to her team mates and then confront her demon (intensional pun here). During this confrontation, Trigon possesses the Justice League members and makes them fight the Teen Titans. This reminded me of the finale of the first season of Young Justice (2010-13). Young Justice handled that scenario masterfully and I still revisit that episode every now and then, but the current release failed miserably in creating any suspense or excitement. I found myself cheering for Trigon at certain points...
I also didn't like how this movie handled the magic and fantasy elements of DC. Again, referring back to Young Justice (or Justice League Unlimited before that show), heroes such as Dr. Fate, Zatana, and Zatara were developed really well. On the other front, Marvel also managed to present the Dr. Strange character compellingly in the direct-to-video movie of the same name in 2007... I mentioned all these things just to say that I enjoy the fantasy element in comics, and the reason I didn't like this movie wasn't because of "magic". Because of loose plot, unlikable (or even antagonizing) protagonists, and boring pacing of the movie, I give it 3/10.