Looking for feedback about ShipAid integration

[LizGolsby6]

I was wondering if anyone has used the ShipAid integration with their Shopify site and would like to share any feedback about their experience. We are looking at using it for our website but were a bit worried that it may 'put off' some customers to pay extra for this 'guarantee'. 

Is it based on the amount of orders that use the option, or is it based on the total amount of orders through the site (even if they do not choose the guarantee). 

There are only positive reviews on their app on Shopify, but this does not always tell the full story of a customer's experience at times.

Thanks in advance for any feedback that anyone may have 🙂