There's a lively discussion over at MacRumors where people who just bought the new 13" MBP are reporting that Apple has limited the SATA transfer speed to 1.5Gb. That's for 2.26 and also for 2.53 version. Previous UMBs have 3gb SATA. Someone claimed that he had a phone conversation with Apple engineering and was told that "it was done to reduce the cost". People are still trying to verify if this is just a bug that can be fixed or if this is in fact what Apple has done. (see Apple discussions) From what I've read, SATA transfer speed matters for people who plans to use SSD while its not much of an issue for people using Hard drives. However when SSD prices drops, and people can readily swap their HDD for SSD, it's a different story.