Some people have said that the new MB have less batt. life not true. Apple's website list the new MB has having 4.5 batt. life while the old 1 had 6 that is because apple is using a different test the new ones have better batt. life due to the new more power effect processors. About the speed the new are MB are 100MHz-200MHz faster but have a smaller L2 cash so basically you wont notice a difference but the new ones still have more batt. life, bigger HDDs and more RAM and they are cheaper I no this for a fact I own the Nov. 07 model and the Feb. 08 one. These rumors are most likely started by new MB owners who were suprized by the early updates.