Shopify Product Network

The app is a bit out of control. You have no control over which products show up on your site. They show related products, but some of the products weren't even related.

You could exclude by vendor, but not by product. You don't even know what vendors are on because there's no list in the admin for the app. I'm sure Shopify will fix this in the future, but I don't recommend using this app until that controllability is integrated into the app admin.

Customers do not understand that they are placing multiple orders in one checkout. They go to one site, add products to the cart and think it is all one order. This creates confusion due to multiple charges on CC and shipping charges. Customers do not get discounts on products from other stores even though they put a discount code at checkout. If other stores mess up the order, customers do not know who to reach out for assistance.
Shopify provides very little information regarding orders and how commissions are calculated. There is very limited ability to choose what will be advertised on the site and many products are unrelated.

It's a great way to extend your reach as well as earn advertisement placement income without modifying your website. My only issue is with Collection placement. If you choose to have Network products appear in your collection they will appear in all of your collections. I would rather be able to pick and choose which collections I'm okay with other products showing up in.