I have bought both of these and one has to go back! They are both really nice on hence my dilema!! They would be mostly worn with jersey dresses and skinny jeans with black ankle lace up boots that I got in Aldo a while ago.
BTW I didn't pay full price for the Whistles one, I used the Grazia 25% discount if that makes a difference.
Funnily enough, I am considering the same 2 coats plus a reiss one which is even more hideously expensive. I haven't tried the Whistles one on yet but thought it looked very nipped in at the waist - did you find that to be the case? Very tempting with the discount. Couldn't justify it otherwise. My last 3 coats have been from Zara and I fancy a change.
Zara usually wins out on quality for me. I think I prefer it as well.
Also, depends on whether you buy a new coat every year or will have it for a while....too "fashion" will date quicker. Will all the leather on the whistles one mark it out as this years coat, for example?