You can figure out the Brownell's discount in the regular printed catalog (not online) if you know the secret code. Look for a series of letters and numbers like this:
AG77B42 = The discount price is $77.42 (the AG & B are irrelevant letters)
...but some items offer no discount. Why? Who knows. Usually it's gunsmithing tools and the like. These items are coded as:
GH00N00 = The 0's in the price mean that there is no doscount.
For Midway, you just need to log in to their website with your FFL account (C&R or otherwise) and the discount prices show up.
As someone already said, the discounts are variable, sometimes big and sometimes not much. I typically shop the two against eachother, but with the C&R discount I do get, I virtually NEVER buy from anywhere other than these two stores.