I just made a quick test on my tablet with Moon+ Reader Pro and at the very least using highlighting isn't particularly intuitive.
Two issues are relevant here:
- I'm a new user - bought the program 2 days ago. So my lack of familiarity, and the possibility of outright user error, are relevant.
- I didn't create the PDF, so it is possible that it is one of those "image of text" PDFs and not one with real text inside of it.
I was able to place a yellow note callout, stickynote, word bubble, or whatever with some dummy text inside. But no, I could not seem to highlight text with my quick test (3 min, tops).
PS: For what it's worth, I know that Mantano's reader is supposed to have a problem with highlighting as well. I remember seeing that in the user reviews.