I'm not sure where all the hate is coming from for this app. The documentation needed to prove your identity is completely reasonable - a copy of your drivers license and a bank statement showing your name or your business name. You can choose to pay $40 per month, or pay a per-item fee, so if you aren't sure you'll sell a lot of product, you can avoid a high fee. These measures make sure the Amazon marketplace is populated by real businesspeople; it's a small price to pay, frankly.

That being said, the process of transferring your inventory data to Amazon is pretty cumbersome, unnecessarily so IMHO.

1. If I have 3 identical red shirts in 3 different sizes (S-M-L), I click "size" for my variant type. It loads the 3 sizes in, so I click on "Small" to create that variant, and I have to fill in the color "red" for each variant - why can't I assign a color to all three? Then I have to choose the photos for each variant, even if the photos are the same for each variant. Again, that should be a universal property. Then, the app limits me to 4 photos per variant, even though Amazon itself allows many more than that, so after the listing is created, I have to go add more photos in Amazon itself.

2 - It's possible to accidentally hit "enter" and submit your listing for publishing, and there is no "Are you sure you want to submit" popup, so off it will go to Amazon (unless you are lucky enough to have an error). Well, once you submit it to publish, you can't access it until they either accept or reject it, which can take hours or overnight, so you have to wait to finish that listing - a huge inconvenience that would be eliminated with a simple popup.

3. The flow of information from Amazon to Shopify isn't great. I have 5 listings that show in my Shopify Admin console as being errorred out, but they are active on Amazon. I can't figure out how to clear out those errors, so it makes further inventory management cumbersome.

4. I really feel like it should be possible to choose universal default settings for my store. I own a plus size clothing boutique and sell almost all my own label clothes, with a few name brands in there. I should be able to set my store so the categories and certain listing settings are my usuals, rather than starting over with every menu every time. It would have saved me an enormous amount of time.

All that being said, it's pretty amazing to have a nearly seamless connection between the 2 sales channels, and I had customer interest within 24 hours of loading my first products in.

The bar to sell on Amazon is really high. Just to get started you have to agree to pay $40/month. Then the registration process get's bogged down with errors. Finally, if you get through that, you will have to submit as much documentation to prove your identify as you would to get a new drivers license at the DMV. Then, they'll reject your ID verification without an explanation as to what's wrong.

Meanwhile, international sellers are running amok selling counterfeit or misrepresented products.

Fun times - I'm about ready to give up. Being almost poor might be easier than dealing with Amazon.

The app does not connect to the shopify account and keeps showing this message since months "Couldn’t access your Amazon account
Confirm Shopify has access from the Amazon MWS developer permissions section of Seller Central. It can take up to 12 hours for Amazon to confirm access.
The worse thing is that there is no support on this topic from shopify since gurus don't have a clue about it.