Hello, I just bought the pro version on Windows and still in trial on my iPhone.
The main argument in favor of Diarium is that it is a one time payment. On the long run it will be way less expensive to use the app. The price is reasonable with regards to the features.
I like the multiple cloud integrations. Personally using onedrive.
I like to be able to start writing on my iphone, and continue on my desktop windows.
I like the ability to export.
My top feature request would be the ability to add inlines images into text, like in Wordpress. I know it is a lot of work for the developer but I really do think it will be worth the efforts and that it will bring more users.
One concern, I read there is only one person behind Diarium, so the app could stop to be maintained with short notice depending on the good will of Timo. But thanks to the Export feature, I think it is a risk worth to take.