XYZ Computing has posted a review on the Lenovo ThinkPad X61 and X61s Notebooks

Overall, not a lot has changed from the X60. The system is still the same old 12" ultraportable that so many road warriors have come to appreciate, it still has that conservative ThinkPad styling, and- you guessed it- still no optical drive. There is good news though because changes were made inside the system. The biggest move was an upgrade to the notebooks' platform as the new systems use Intel's Centrino Duo technology. This platform, which affects the wireless, chipset, and processor, is also known as "Santa Rosa" and marks an appreciable evolution in notebook design. Another change is that the processors were upgraded. While the X60 moved up from one set of Core 2 Duos to another, the X60s had a major change as it moved from a Core Duo process up to the new Core 2 Duo line. The X61s still uses an ultra low voltage processor, in our case the L7500 (1.6GHz), but the move to Core 2 Duo should have a nice impact on performance, or at least a more significant than that see on the X61.

Lenovo ThinkPad X61 and X61s Notebooks Reviewed