I have tried a few Japanese schools over the last couple of years I came to JACS early 2003. Prior schools had all adapted the same methodology, cram as much content into a fixed amount of time as possible.But speeding through chapter after chapter only left me with a weird feeling of frustration, constantly adding to the pile of "things to memorize when I have time, later". That didn't work well for me, very little stuck in my head and I was able to use even less in daily life situations.
JACS has a much more individually tailored approach. The humoristic and skilled teachers quickly identify my weaknesses and they keep repeating those parts until they stick. I finally get to learn phrases and grammatical constructs in a way that makes it possible for me to use them outside the classroom situation.
There is probably no effortless way to learn Japanese, but with JACS it is certainly a lot more fun and I know that I'm constantly improving.