App works well for Shopify to QBO. Had a hiccup in syncing, and asked OneSAAS for support by email. Hazel got back to me quickly with a fix.
Would rate app 5 star -- but have to take 1 star off for the fact the sync stopped working for no reason, and required an intervention to fix.

App does just what I need it too - all my sales chanels are synced :) Really helpful customer support. That's always good. Thanks Hazel!

EDIT 5/27/19: The refunds issue has been fixed. However, there is still a bit of manual entry as the software is unable to determine if an item was restocked in Shopify, so it defaults to 1) restocking the item if all money was refunded or 2) only returning the money (and not the product) if only a portion was refunded. Still a great interface, but a bit cumbersome if you offer a "money back guarantee" or any instance where the product would be kept when funds are refunded. Still can't say enough about the level of service and follow-through from the team: Hazel, Troy, Vincent, and Marck - they are all amazing!!
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EDIT 4/23/19: While I still think this is a great app, they still have not been able to fix a bug that prevents refunds from posting to QBO. This has prevented 186 transactions and required me to hand key each and every one. I/They have been aware of the issue for 2 months and there is no timeline as to when this will be resolved. I will update this review when it's been fixed.

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Best app on the market - hands down! I tested several for my clients and landed on OneSaas for their seamless automation and easy but robust setup. As an accountant I love all the options they provide (chart of accounts mapping, seamlessly adding new inventory items into QBO, inventory update sync, etc.) as it makes my life a whole lot easier.

The best part; however, is the AMAZING customer support team. I've had a few bumps along the road and they have been there to quickly and efficiently handle every situation I've thrown at them. I think I've spoken with almost the entire support staff, but mostly I've chatted with Troy and Hazel. They are very friendly, knowledgeable, and often go out of their way to ensure everything is handled quickly.

Stop considering and just do it. You won't be sorry.

App has freed up a lot of labour hours.
Very responsive staff when you have technical problems as well. Marcks been a champ.

Works perfectly, OneSaas support are helpful. Only limitation that we found annoying was you can't set up a workflow where OneSaas tries to push an order from Shopify to your accounting system (Saasu in our case) as a Tax Invoice first, then if stock is not available (negative value) then it will push it through as a Sale Order. You can only choose either to sync all orders as Tax Invoices or Sale Orders. Then you either have to go into our accounting software and manually change all the orders into Tax Invoices or wait for pre-ordered stock to arrive before OneSaas will push the orders into Saasu as Tax Invoices. Would give 5/5 if this became a feature.

Would not want to be without it. Saves so much time every day. Support is great. Would give 5 stars if they could import gateway fees and import the prefix along with the order number. Would give 10 stars if they could handle returns/refunds.

Great tool, great support! I tried another Shopify-Salesforce connector but it didn't give me the line item detail that I needed. OneSaas was a breeze to install and sync'ed all my client info, products and orders automatically. And it created a separate record for each product ordered, attached to the Opportunity - exactly what I needed. And for the questions that I had, Adela had all the answers (via chat) in a very timely manner. You just don't see great customer support these days, but OneSaas has done it right!

UPDATE: I have uncovered a rather critical problem with the OneSaas Salesforce-Shopify connector which has caused me to reduce my rating to 4 stars. While the Shopify connector pulls all relevant data from Shopify, the contact info does not pass through to Salesforce. The contact name is embedded in the opportunity name and the phone number is stored in the Account.Phone field, but no contact record is created, and the email is not passed to SF.