I have Inkpad 3 and Inkpad X and I'm kind of disappointed in X. The main reason for disappointment is that it is remarkably darker than 3, seems that it has the same frontlight (resolution is the same, too), but because of the bigger screen it is a bit weak. Since I'm used to Inkpad 3 it is inconvenient to go to dimmer screen. In order to maximize light I have to adjust it to yellowish (blue frontlight is weaker), so also light temperature is "ugly", not quite paper-like. If it had brighter screen I would recommend it, but now... I think I would recommend iPad Pro for pdf-s, at least to compare before purchase (yes-yes, I see author bought it long time ago- other people then
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