Thanks Nivi78 for your YouTube review. Simple & fair. I've had my V3 for about 3 weeks now & I am very happy with the device. Have read a few books & decided my preferred format is FictionBook (.fb2) files. It has the most flexibility in terms of resizing fonts etc. I agree with Nivi78 that PDF performance is a bit hit & miss, but other formats such as doc, txt, epub & rtf all seem to perform quite well.
I have a lot of books in MS Reader format (.lit). Currently I am using ConvertLIT to remove DRM if present; ABC Amber LIT Converter &/or Book Designer 4.0 to convert to FictionBook format. This works really well, with minimal editing required but it would be nice if someone came up with an open-source version of MS Reader for the V3.
I think the V3's readability is excellent - no eye strain or fatigue. Just as good as paper. The device is robust & feels solid & comfortable in the hands, but I do think the leather cover is essential. You can even clip a booklight to it for reading in bed.
I bought the Hanlin V3 specifically for reading books rather than technical documents, & after a bit of trial & error with various formats I am now very happy with the experience.