I didn't how to answer your questions since it all depends on how much you can earn on the two options. Anyway, I want to say you posted twice in this forum.
I thought you're talking about Manga Rock which was dead for a few years now... Also Rest In Peace Tachiyomi. You're a great app, I'll miss you.
Anyway, the only manga that I read out of all Hiro Mashima's works is Fairy Tail and I liked it, I still haven't read the sequel though.