Ours are not the same. I cannot tell you what exactly they are anymore, but we have three different in a U shaped kitchen. It works just fine. The widest aisle is at the bottom of the U, perhaps that makes a difference. The two "legs" of the U are probably 2" or so different. It's fine.

Not at all! Ours are quite different - we have more space on the traffic side where there is island seating. It doesn't look off at all. I think most are a little different. Don't worry! : )

Ours are very different - over 45" on the long leg of the L with the rangetop on one side and the fridge and ovens on the other. 36" on the short leg with the dishwasher, baking and coffee area. I think it's fine - the wide one works well because there are often people going by or working on both sides of that one and the narrow one works well because there I'm often using counters on both sides and can easily reach both.

Nope!

~36" along one side, and 42" (43"?) along the other.

mine are wider in the areas that get the most traffic and smaller in the areas where we are more likely to stand and chop.
I think 36 is minimum and 48 would be max....

No, from a looks point of view it will be fine. (Functionally, at least in a two-cook kitchen those widths may be a bit narrow, but w/o a layout drawing to look at, one can't know. it al depends on who, how many and what task is being done on the counters, appliances or surfaces that abut the aisles.)

Varying aisle widths is also an important tool for subliminally directing traffic to where you want it to go. For instance, too much aisle width in a work area combined with skinnier aisles where you want traffic to flow will have the result of funneling people into the work space.

L.

We have 36" for the side aisles, and 42" for the back aisle, where the sink is and most of the prep work and traffic is.