Nanette, a few of us are really hoping to get an answer to the Advantages/Disadvantages question. But I can tell you that the main DIFFERENCE is that the 6 month rotation has you repeating each week before moving on to the next week's set of DVDs. In other words, you do:
week 1, discs 1,2,3
week 2, discs 1,2,3
week 3, discs 4,5,6
week 4, discs 4,5,6
I believe the only mesocycle that DOESN'T repeat is Meso 3, but I MAY be wrong on that one.
I just recently changed my mind to the 6 month rotation. I started with week 1 (discs 1,2,3) and moved onto week 2 (discs 4,5,6) this past week. But starting tomorrow, I'm REPEATING week 2 (discs 4,5,6) and will follow the 6 month rotation from here on out. Personally, MY PERSONAL advantages of doing the longer rotation is that it will keep me ON TASK longer. I also feel that repeating the week allows me to 'learn' the disc the first time thru, tweek my numbers, and really WORK WORK!
I hope this helps. But like I said, a few of us are hoping to here from Cathe or SNM concerning the advantages of this longer rotation!
Gayle