I am a big fan of the Canon 24-105mm f4 IS kit lens and I also often shoot with the Nikkor 24-120mm f4, which covers a greater range, however isn’t as good optically as Canon’s counter part. I have a Nikon version on preorder from BH (also available in Canon mount), and just came across the first MTF test here on photozone. If you are interested in this lens, check out their test report.