Hi - I'm going to purchase some of the Jillian Michaels DVDs. Right now I'm thinking about 30 Day Shred and Ripped in 30. I'll get another one, but not sure which one yet. On Amazon, I see that there are various years for these dvds. Does anyone notice a major difference between the older (2009 and 2010 versions) compared to the 2011 versions? Since the 2009/2010 versions are cheaper, I could get more DVDs. Thanks!