I was unfortunately not able to compare these two very similar totes side by side since I ordered the Madewell Tote first, didn't care for it so returned it and then purchased the Cuyana Classic Leather Tote.  But here are some of the similarities and differences I noticed between the two bags (also you can read a whole reddit forum discussion here).

First the dimensions: The Madewell Transport Tote (in black, with tan handles) measures 14.25(h) x 14.25(L) x 6(w) inches with a 8.25 inch strap drop.  The Cuyana Classic Leather Tote measures 13(h) x 18(L) x 5(w) inches with a 9 inch strap drop.  So the Cuyana tote is a a little shorter, but a lot wider.  However, since the leather on the Cuyana bag is so soft and smooshy, it's quite easy to fold in the sides a bit to make it less wide (like the picture below).

Though the totes are really similar, here are the reasons why I think the Cuyana tote is better:

-First off, the leather on the Cuyana tote is amazing.  It's super soft and smells wonderful. The smell reminds me of the leather of Balenciaga bags, even though the textures of the leather are different.  The leather on the Madewell tote is stiff and feels and smells like cheap leather.

-The difference in the leather is probably due to the fact that the Cuyana tote is made in the US while the Madewell tote is made in China (plus Cuyana is a brand all about producing top quality items).

-The strap of the Madewell tote is a just a tiny bit shorter, but it can make all the difference when trying to wear a tote bag over the shoulder when wearing a winter coat.  I think the Cuyana bag might fit, while the Madewell tote most definitely wouldn't.  

The Cuyana tote also comes in 3 different variations: the classic, the tall tote and the zippered tote.

So as you can see, my vote clearly goes to the Cuyana tote over the Madewell tote.  But if we were to have a broader discussion about all the totes that I own (including the Mansur Gavriel Tote —reviewed here—and the Everlane tote), I would have to say my favorite is probably the Everlane tote.  I love the smaller shape, the adjustable straps, and the two deep interior pockets with snap closures.  The Mansur Gavriel is good for just piling things in, and it holds its shape really well.  I think in general I'm just not a soft tote kind of gal.  But if I were to choose one, it would definitely be this Cuyana tote.  

Have you guys checked out Cuyana before?  I'm in love with their products and their site

I personally purchased all of these totes and were not paid in anyway to make this review (just trying to help fellow-tote lovers!)

{Feb 2019 update: Things have changed in the 2.5 years since I've written this review.  The leather on the Everlane petra tote stiffened up and became rubbery, which I really disliked so I sold it.  I also did not keep the Cuyana and Madewell totes because in the end I wanted to limit the number of totes in my closet.  I have a friend who used a Cuyana tote consistently for 1.5 years and the strap broke on her.  Also I had the Cuyana Leather Travel Bag for a brief time but also sold it because I found the leather quality on that to be not as great—it was very thick and pebbly.  So what totes am I currently using?  I love my Celine small cabas tote (reviewed here) and my Everlane Day Market Tote (reviewed here—which is very different and better made than the original line of heavy Petra totes IMO even though the leather is of a thinner quality. You can see how the Everlane Day Market Tote wears even after 100 uses here). I also love Cuyana’s Classic Structured Tote since it has an extra layer of microsuede on the inside to allow the bag to stand up on it’s own and make the bag overall less floppy. If I were to get a tote bag to replace my Celine one I would probably go for this one. However if you’re in the market for a lightweight, slightly floppy tote then Cuyana’s Classic Leather tote is the one for you.}

P.S. My friend has Cuyana’s small Carryall tote in stone and has been using it almost daily for at least 4 years. The long crossbody strap broke in year 2, but the bag itself is still going strong, which I think is a good testament to the quality of the leather Cuyana uses as well as it’s durability (well except for the strap). She replaced the strap but here she is modeling her very well used Cuyana tote for me: (also she’s tiny so the small bag looks huge on her fyi)

{January 2021 update: For those of you guys on a budget, Quince (also known as onequince) has some very similar totes for about half the price. Quince is an ethical company that contracts with the factories directly in small batches at the best possible prices (thus also preventing waste by not overproducing a certain item). My review of the Quince leather tote is here (where I also compare it to Cuyana’s leather). I would say Quince’s tall tote is like Cuyana’s structured tall tote and not the floppy one I reviewed here. Quince’s selection of totes can be found here. But if you’re looking for something like the Cuyana structure tote, unfortunately they don’t have anything like it anymore.}