In terms of
Moon+ Pro, here is my current recap of where it seems to be lagging behind Marvin:
- no option to customise the size of 1st-line paragraph indents
- missing back/forward navigation buttons when reading books – at least I can't find them. Marvin is missing the forward button(s), which is bad enough (see GitHub #50), but a missing back button is truly troublesome; you can't even briefly look at a different section in the book without losing your current place...
- rendering fidelity (even if you completely disable the "Override CSS" option in Moon+ Pro, its rendering fidelity is lower compared to Marvin -- though the books look very nice in both e-readers, and, in fact, to me they currently look even nicer in Moon+ Pro than in Marvin, thanks to the background texture options)
- no true full-screen mode, at least not on the new Nexus 7; the bottom Android bar with the 3 standard menu buttons keeps popping into view whenever you touch the screen; seemingly the only way to avoid that, is turning pages using the volume button (see here)
I have e-mailed the above issues to Moon+ Pro's support email address; let's see how much "customer support" one can buy along with a €3.80 app, although to be honest, that is such a low price I am surprised any customer support is explicitly offered as a "Pro bonus". I remember I was pleasantly shocked

, back in December 2012, after receiving a reply from Kris within a couple of hours after sending a support query to him. I thought, "What's this? Amazon keeps ignoring my issues for years and years, and the developer of a
free app responds within a couple of
hours?!"