This is quite possibly the worst application I have ever used in my life, and I worked with it almost everyday for 6 months this year struggling to link all my products correctly to Amazon until giving up and going to an App called Koongo (which has been tremendous by the way - would highly recommend). The few times I did reach out for support I was told to "ask Amazon" or "that's an Amazon thing" essentially blaming Amazon and offering no ability to problem solve or offer support. It's a poor excuse for an app (if you can even call it that) that times out frequently or gives broken links in the middle of linking, does not map or identify the correct products, has very little customization within each product, and has no search function or dropdown filters to actually find your product quickly (super frustrating if you have a big catalog and have to constantly scroll down and hit next). I'm not even mentioning all the issues i've faced - the above are just some of the main ones I experienced. To be quite frank unless you have a small assortment of fewer than 50 SKUs you'd be better off manually listing your products on Seller Central. Don't waste your time with this until Shopify decides to take multichannel e-commerce seriously and dedicates developers to making a user-friendly and non-broken app. I'm hoping that someone reading this does not have to go through the same frustration that I did for so long.

Useless.
1. It does "not" create new listings. It just gives you a link to open Amazon's website to manually add a listing.
2. It does "not" sync Shopify to Amazon to keep prices in sync
3. It does "not" keep description and pictures in sync
4. It does "not" let you know which styles are in sync.
5. It only syncs inventory.
6. Description of the app is inaccurate. Support has acknowledged this.

This app does not properly sync inventory -- defaulting to 100 units in stock. It also largely to fails to update inventory when items sell. Additionally, the linking products procedure is painstaking and un-intuitive. This app fails on every accord.

doesn't sync at all and ive tried for over a week now. maybe something is wrong with Shopify because ive done everything correctly

Very basic app with many issues. Might as well list manually on Amazon Central. I get a server timeout error every now and then when submitting a product. I suspect most of the issues are on Amazon's side of things, but they did not develop this app. Products variations do not always map to correct items on Amazon. Product attributes are limited... Images don not upload although they are selected. I have to upload the images again on Amazon. Many categories require approval and many brands require the seller to be an authorized dealer. I like the eBay app much better. Most probably going to ditch it and either use another solution or do everything manually from Amazon central.

Update: Reduced to one star. Many server errors "502 Bad Gateway" when submitting items.

This doesn't work. At one put I linked a few listings. I must have hit it on a good day or something. However, now it won't link any already existing products or create a new listing. This makes it completely useless. Plus it tells me I need to link the products I already have linked.

This app will not sync to my store. It has been over 24 hours since I have tried to integrate Amazon and Shopify, and I continuously get the same error message which reads, "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."...

It does not import Seller Fulfilled Prime orders, which makes it unusable for us. If you're not using SFP, it's probably fine, but for us, it's not usable.

This app is terrible. You cant search for products. How do you create an app to show you products listed on amazon and you dont have a search function?? Beats me. This is such a basic essential thing. Listing products to amazon will take you months if not years if you have a couple of thousand products because it has to be done one by one through many steps. It does sync orders and inventory. I guess its the only good thing about it.

You must allow them access to all your past and future orders and all your customers data to use the app. Then you need to pay them $39.99 a month to have the app integrate with your store. Much easier to just create a regular amazon seller account plus you wont have to sell out ALL your customers and their data. Just a fancy data grab by Amazon that they actually expect YOU to pay them for. UNREAL!!