I'm a paying customer. It's not that much money. The seamless/instant sync is why I pay. He could use a few more features, which I did email him about them.
The one lesson I think people should get out of this again is that it's really hard to get consumers to pay for a nice to have, here as if you solve a real business problem, companies will pay a lot more.
Sorry, it's weird to me. More power to the author for finding a revenue stream but it certainly brings out my cynicism. The revenue stream is on a house of cards since there is no "service" being paid for and the fact the author is asking $125k for such a fragile revenue steam is just strange.
How is synchronization not a service? It requires maintaining remote servers, and someone has to pay for them. Not that I think the price is reasonable, but that's a different matter.