When it comes to epub format ebooks reading, Aldiko Book Reader is the best Android app on Earth and nobody will oppose it, as I think. I have been using it for 5 months and really satisfied. Now, I am thinking about purchasing its premium version in hope to get more useful features. But, I am unable to find what I'll get new with premium version. Its page on Play Store doesn't have anything about "Premium Exclusive Features". Please, help if you've used premium version.
Answer is in their FAQ:
The free version is advertisement supported while the premium version is not. Both the free and premium versions have the same set of features at this point except the premium version will get faster updates.