The reason I usually hate subscriptions is that they are a headache remember, changing credit cards requires me to remember and update subscriptions in many different places, and providers make it hard to cancel. My experience with subscriptions on iOS has been very positive. It's easy to pay for and easy to cancel.
Personally, I would rather pay a small amount per month while being able to cancel at any time than pay a larger amount up front for something I've never tried. If the app is compelling enough to keep using, I'm happy to keep paying.