I quite liked ReadEra. Scans your phone for all epubs, allows grouping and organizing them, but most importantly, has a good looking, customizable reading interface.
"Cool Reader GL" is good. Has a lovely page curl animation, etc. It's old though, and hasn't been updated in many years now but it still works fine. I like it because it's very customizable and has fine control of font rendering such as being able to turn off anti-aliasing. It takes time to set-up the way you like, but once you do, it's great and just works.
