I think the "best" method of learning is what works for the individual, MeNoSavvy. I agreed with you for the first 6 months of my studies. I did Pimsleur, Japanese for Busy People, and RTK simultaneously.
I stopped about a month ago because I quickly got to the point in which I felt the need to be able to read a real Japanese sentence. I've been concentrating on RTK ever since late April and if I don't lose my momentum, I'll be done with the book and able to concentrate on new things in July.
I just got to thinking, what's the point of using my Grammar Books when they'll be introducing kanji soon, in direct competition with the RTK method that I'm using? And how am I gonna study for JLPT in December, with all these words using kanji, if I don't know how to write or recognize the kanji? Dividing the work and doing 3 methods at once was fun, but the pace was slow and after doing it for long enough, I really felt like I needed to start doing *something* to get my kanji up to speed. So, I revised my methods and I'm very happy with the results. I still have my vocab and grammar in an SRS, but I've stopped trying to learn new stuff till 7/1.
We all have different goals, mine is JLPT 4 for now, because if I pay for a test and have to travel to get there, I won't slack off. I don't think there's a best or worst strategy, we just all have different goals, and different methods of studying to get us there.