While I am very interested in the Duplicacy offering, I am also very uninterested in purchasing software on a subscription. Do you offer a permanent license option?
Subscription services only benefit the vendor. They are a form of extortion where the vendor demands a fee regardless of any additional value being added to the product. If the extortion fee is not paid, the software ceases to operate. (This, by the way, includes the loss of functionality if the vendor goes out of business. A common problem with small companies.) Without an ability for the customer to negotiate payment for services, e.g., paying for additional value provided—a version update, there is no incentive for the vendor and the customer is simply wasting money. (Subscriptions require a vendor to be benevolent—a quality businesses and people rarely exhibit.)
I do believe in paying for support and for additional services, i.e., the traditional license and support fee structure. If a vendor provides enhanced functionality and support services, they deserve to receive remuneration, either in the form of payments for new version releases or for continuing support services. I am not, however, willing to be held hostage by a subscription fee.
That said, I would also expect that there would be some benefit to bulk and extended purchases. I have about 15 machines that I would like to use the software on, however, at $540/year and $2,700 for 5 years, the Duplicacy software costs would far exceed the cost of the cloud storage. Please let me know if you intend to introduce any significant bulk and multi-year purchase discounts.