I have both the 24-70L f/2.8 vII (upgraded from the v1 that I used for 4 years). Also I still have/use my 24-105L f/4 IS. If you can I would sell the v1 and buy the vII and keep the 24-105L. I think they target different things (IMO). If you travel, then the 24-105L is perfect. If you shoot lowlight/weddings/clubs/portraits/etc) the the 24-70 is great. Also when I walk around the city or goto the museums I use the 24-105L… that additional 35mm makes a big difference… plus the IS is great and worth it.