Hi Bud,
Thanks for your feedback. You can try the entire app for free. In fact, we give away almost the entire app for free, with the exception of the Stereo HD quality. If you are happy with the recording quality that, say, Apple's Voice Memos provides you, our app sounds exactly the same in its free version.
As I'm sure you agree, the best way to compare audio quality is just to listen to it. We have a listening example on our website, but you can try it yourself for free in the app for an entire month!
The Zoom H4n costs over $200. The sound quality of that device will be much better, but I'd argue that the UX of our product is much nicer. In addition to not having to carry around a dedicated device, there are just so many small UX things we've focused on that make working with audio recording much nicer. Take the Time Paragraph for example - once you start using it, it's really hard to go back to a single line for recordings longer than a few minutes.
I get your point about not wanting a subscription for something simple. Truth be told, we're also sceptics when it comes to subscription apps, but as far as we can see it's the lesser of evils. The freemium model allows people to try the entire app for free (and continue using it for free if they're happy with the feature set), and the subscription model allows us to ship major features as they are ready without having to pack them into a paid major upgrade.
There's also a psychological component that people are happy to shell out a lot of money for something that looks complex, but not for something that looks simple. Ironically, making a seemingly "simple" app is a lot more work. There's a lot more in this app than just the audio quality.
In our team, Jan - who also commented here - is also a professional baritone. I used to do classical singing, too, but not professionally. I feel confident when I say that we fully get your use case for recording. Give the app a try, I think you'll like it :-). It is designed for people like you.
Thomas