I have noticed some issues with nopCommerce 3.8 & this plugin over the last month that I have used it. I have no problems listing items, that seems to work well. I have issues with the imported orders and also with inventory synchronization.
1.) I have sales tax configured only for sales within my state of South Carolina, both in my store and in eBay. Other states do not pay tax. When the eBay orders are imported to my store, most of the time tax is somehow accounted for and backed out of the selling price. I have to edit almost every eBay order to fix this.
2.) Profit is not calculated based on the cost of the item like it is for a store purchase - the entire selling price is used. This cannot be edited and is causing my sales reporting to be off (substantially). Apparently I am going to have to go directly to the database to fix this.
3.) I went over my 250 item store limit for free listings so I took a few down by clicking the End Item button. The next day they were back up on eBay. I had to not only End the Item, but I had to remove the eBay Item Id and set the eBay Quantity to 0 to get them to stop relisting.
4.) The biggest issue I have is related to inventory. I have noticed some items with attributes keep getting re-added to eBay with the wrong inventory counts. My store has them at 0 and no backorder allowed, but the inventory on eBay keeps getting set back to what it was when initially listed, not what it is currently. So items that have S, M, & L available, but say L sells out - the next day the large will be back on eBay as available. I have had this happen 3 times in the last two weeks with different items and have had to cancel sales. Unfortunately, this is causing me to lose my Top Rated Seller status later this month (and thus my fee discounts). I have had to put my store in vacation mode until I can figure out how to make this stop happening, but I will most likely just remove the plugin and stop selling on eBay.