I'll happily pay for your service when it comes out. But I do think Rarity brings up a very salient point. I've overseen other projects that transition from a free to paid service, and there is a shift in the demands of the consumer base. Of course you still have control as the developer, but they will [rightfully, I should add] demand more from you. When you're taking in other people's hard earned money, you become a business. Businesses are legally required to uphold a standard that is higher than that of individuals. Anyone who has run any kind of business before, even if it's something small and freelance such as web design or an ebay store will tell you that there are significant additional hassles and holes to jump through. You are expected to deliver expedited service. In other words, this becomes a job, not a hobby. This is not to deter you from making the service, but it's a cautionary message to make sure that you're ready for the additional headache.
