It is perfectly serviceable for reading, though it may lack some of the reading oriented features of other eink devices. I love the large size for some of my documents, which are unpleasant to read on smaller devices.
Based on other comments here, it seems that the Remarkable is missing several features that some people enjoy in their eReaders. The only one I can cite definitively is the lack of backlight. I can't speak to other allegedly missing features because I haven't investigated the issue. I am satisfied with the features I do use when I want to read certain docs on the large remarkable screen.