I definitely agree with you, it's boosted my vocabulary a lot. I've definitely picked up a few small phrases from it too and not to mention I can kind of get by watching raws now and at least understand the gist of what's going on, and I have yet to even start classes. I think it's a useful tool but I probably wouldn't make it your main one, since there's a limited amount of things you can learn from it. Not to mention subtitles aren't always correct.