I'd like to suggest you reduce the cost of the subscription. If everyone paid your current subscription fees for all services we use, we'd be pretty broke pretty quickly. Therefore if you see it from our perspective, with all our differing budgets, a pay-what-you-can-afford model to remove the ads would be better suited to the end users. You'll then attract developing nation not just first world subscribers. Even in the first world I can't afford those fees for everything I want to subscribe to. If you want the current fee $ amount, perhaps make that a remove-ads-for-life fee? The subscription could then be pay what you can afford? In theory though I'm quite happy to pay to remove advertising. Advertising is an assault on the mind. I'm happy to pay to remove it within budgets I can afford. Given I only spend 1 hour a year looking at the Vuze GUI I don't want to spend very much removing advertising from it.
/ps thanks for the great software!