I have a Hanlin v3 as well. I haven't tried to use openinkpot but the problem there is that they still haven't released anything other than this "v0.0" developers only release.
The good news is that they are active.
[...]
About the v3: I like it a lot but
- .chm navigation sucks (important for me)
- opening directories with too many files (hundreds) is too slow
- I find the screen a bit too small
Other than that, if you can control the generation of the PDF you are loading into it (the Guttenberg project has an interface for setting page dimensions and font size & type), then it is quite nice to read on it.