It's been a while, and all the apps, while still functioning, looked dated as they were not updated for the new iPhone and iPad models. Well, not anymore.
All of the apps now fully support all the devices. Some apps have changed a bit their look, but all of them remain simple to use, fully functional and without any ads.
It's important to note that the apps do not require any user accounts, log-ins, any personal data such as email addresses, they do not require passwords or any other modern stuff you can think of. In fact, the apps do not even require an internet connection. This might come in handy in some areas where data connection is still poor.
So, first and foremost, the apps do their calculation job. They strive to remain simple to understand and use, but they do not use fancy user interfaces, and this is by design. What they require is mostly number input.
Second, your privacy and security. No user data. No internet connection. No accounts and log-ins. No ads. No tracking. No third party code. Nothing.
Third, performance. All results are instantaneously available. No waiting for the results, let alone because of bad data connection.
Fourth, accuracy. The apps have been tested for several different conditions. Big numbers, small numbers, decimal input, you name it. Some reviews and user feedback confirm this. But if you find something not working correctly or as expected, please let me know.
So, if you're not convinced, try downloading one of the free apps. Yes, they're free. As in completely free. All the points noted above still hold true.
The App Store link is here: https://apps.apple.com/us/developer/sebastjan-valic/id503687385
Thank you.