The details of my title can be found in my blog at:

http://www.bobkeenanphoto.com/canon-versus-tamron-vc-24-70mm-f2-8-lenses/

But the essence is that I love my Canon 24-70mm f2.8 but for the kind of shots that I do I need the IS.  I had it with the 17-55 when I had an APS camera.

When Tamron came out with the VC version I jumped on it.  Even though I know Canon has great glass and I knew very little about Tamron.

So..... I am happy I made the switch.   Many of the finding in my blog match other reviews and finding.  I used Reikan's Focal to verify some sharpness info.  The Tamron is sharper at 70mm, the Canon better at 24mm.  There is some vignetting at 24mm on the Tamron.  I have not seen the onion bokeh.  I think the bokeh is nice.

Bottom line its a good lens and that VC makes my day!!

Good read.
Canon 24-70 IS is on the way, lots of money though. 

There isn't a Canon one on the way yet not even on the rumor sites is there?