I bought a Boox Poke3 a couple of years back and it's honestly the best purchase I've made in a long time. I previously used a cheap Tolino e-reader so I have some experience in the difference between an e-reader and an e-ink tablet with android. In all, I consider the tablet to be well worth the money I payed for it. Regarding the battery life, while it is true that the tablet does not last for as long as an ereader, the battery capacity is still large enough so that it only requires charging once in a week under heavy use. That is unless you use the wifi, which will drain the battery quite faster. For comparison I charged the Tolino once every three weeks. Having the ability to install Android applications is a game changer in my opinion, especially if you wish to use a unified method of reading articles (like Instapaper or Pocket). E-ink Bro is extremely useful too. The Boox tablets have a magnificent way of side loading books (and files in general) called Boox Push which allows for direct control of the tablet filesystem from the browser of another device, phone or computer. Just scan the QR code with the phone and you can transfer, move, rename, etc any file you wish to. I can not stress how convenient this is since it works with or without an account, it can connect using the local IP of the table and transfer files over the local network. The backlight options are also great, Boox tablets can control the warmth of the backlight to reduce eye strain when reading at night. Another great feature is that the tablet is extremely light, making holding it very convenient. I think that the Page model is bigger though so I don't know about that. As far as I can see the Page has physical buttons too while the Poke doesn't. Finally, the performance of the tablet is good as far as I can tell but I have heard from others that generally Android tablet are a bit slower than ereaders. I use KOreader though which is very snappy.
Also, does anyone know how often the Boox store restocks them? It’s been showing as unavailable every time I check over the past few days.
I bought mine over a local vendor and not from the official Boox store so I can not answer you that, my guess would be that depending on your location this will vary. I would suggest that you check some reseller company in your area.
I bypassed the Dark mode limitation, at least while reading, by using KOreader. This little ereader allows to bind settings toggle and other utilities to taps in the corners, thus I toggle the Dark mode by a single tab. I can not recommend KOreader enough for a Boox tablet, Neoreader is good but KOreader is on another level completely. Also way faster than anything else I've tried. It may have a steep learning curve but it's 100% worth it.