[raysa]

I have an Onyx Boox N96ML (almost 10-inch). The screen is great in sunlight - or indeed in any conditions - but it suffers from the sluggishness that you mentioned, Guy, in relation to these older models. The other problem with it is that the use of colour in MobileSheets for menu labels, etc, makes some things very hard to see on the monochrome screen. There is a MobileSheets version for e-screens which I assume overcomes this but it requires Android 5 or later, and this old Boox is only Android 4 and doesn't seem to offer a way of upgrading.
The Max 3 presumably fixes both of these problems ... but ouch - the price!
Like Bazza, I look forward to hearing how you find it.