Anyone been using it? How is it working for you.. subjectively?
Other than it's less-consistent across-the-range performance and likely less rugged build than the Canon, I don't see much for drawbacks to the Tamron for shooters who don't need best-in-class gear in this range.
I recently bought this lens (about 3 weeks ago) to replace my stolen 24-70 f/2.8 L II lens.
I am no expert who shoots brick walls and what not, but my thoughts on this lens are:
Value for money when it comes to image quality
Build quality is far below the cheapest Canon L
lens ... (see my youtube video on this here Tamron 24-70 f/2.8 VC Lens Review
VC on this lens is better than Canon's Image Stabilization on EF 70-200 L IS II lens ... I recently made several test shots, handheld, to compare Image Stabilization at 70mm on both lenses (I will be uploading those images during this weekend).
If you accidently drop this lens even from a modest height, it most likely will break.
Although it is no match to Canon 24-70 f/2.8 L II (which is absolutely sharp and a delight to use), the Tamron 24-70 VC is a very decent lens that will statisfy most photographers with its optical performance.
If I had the money I would buy the 240-70 f/2.8 L II again ... but if I lost Tamron 24-70 VC, I would not buy it again.