Our v3.0.1 release wasn't enough to move the needle much on our monetization strategy. At one point, we had about 11,000 active trials but we've only closed 49 orders as of yesterday.
We have three major problems still in play:
v3.0.1 is plagued with some java errors that we've fixed in v3.0.3. We uploaded the new version with bug fixes on 12 January but Google has yet to approve our release.
We have a separate code branch with new features like Notifications off (requested several times), battery improvements via automatic enable/disabling of the Bluetooth radio (not user requested), ads for the free version, and improvements to how we discover and identify Bluetooth devices that we need to finish and integrate into the current version.
We haven't figured out what makes our buyers tick. Clearly, the features we offer today aren't enough to get a larger percentage of trial users to buy. I have other ideas that I think would be a differentiator from both our competitors and the Android OS that I suspect will help make a difference if we market it right.
Update: we've had 51 orders and 3 refunds for a total of $70.86 since we changed over to IAP. Compare that to 19 orders, 5 refunds, and $37.99 for pay to download.
I'm no longer paying for a Google App Ad so our downloads have significantly slowed down but that's okay. I'm not going to focus so much on downloads until we get further down the road. I've proven people will download it. Some will use it and some will uninstall it. Once we figure out how to better monetize it, slow our uninstall rate, and improve our conversion from free to premium, we might look at paying for an ad again.