Opticallimits

Just found a mint condition second hand Canon 10-18 for just 180$ didn't hesitate.

Now since I have both worlds APS-C and full frame. Will do my tryouts to decide which one to keep.

In favor or Tokina 16-28: Fast lens, less sensor noise since full frame. It is optically by far the best choice only if it didn't weigh 950 grams a true burden for hiking, however for weddings and parties it's simply amazing.

In favor of the Canon: Practical, lightweight, compact, can take filters, no protruding front element less than one quarter the weight of the tokina...

Just to mention also got 8mm fisheye quite funny lens

Most likely I will be keeping both, unless I have a very decent offer for the tokina 

The answer is easy.  Your wife bought you the 16-28 as a present, so that's the one you keep.

Keep both, what's the problem? Then just take the one suitable for whichever camera you're using at the moment.

I am trying today the EFS 10-18 to see how good it and it can match the 16-28, however I got a pleasant surprise from my 8mm fisheye..., flare spots are a slight problem, but I think it is avoidable