Books

Okay so I'm somewhat knowledgeable on the topic AND have been going through a similar dilemma recently, trying to replace my aging Kindle Oasis 10th gen (battery barely makes it to two hours reading time sadly).

There's a few aspects you need to consider.

First, what is your intended source of EPUBs? Do you want to download them manually from certain sources, or do you plan on using a specific store? The store itself might be a decision factor. Kobo has its own store and the prices are quite okay, but you don't truly own the books (unlike with Amazon, unless Kobo's licensing changed - last time I checked the "buy" option was just a perpetual license that could be withdrawn at any moment).

Hardware-vise, the Kobo Libra Colour and the Boox Go 7 Colour (albeit I'd recommend the 2nd gen version, for the added speakers and mic), are about on par. They use the exact same Kaleido 3 display, with the exact same issues (due to the colour display there's a distinct 45 degree line pattern, I'll try to attach an example image in a reply; there's an increased amount of ghosting compared to standard Carta 1200/1300, and anti-aliasing doesn't work as well, so the text might not be as clear, depending on the font you use).

Software-vise I found Kobo's offering super lacking, and the core hardware is considerably weaker; which meant KOReader, after the straightforward jailbreak, didn't work as well as I expected it. Lots of freezes, lagging, crashing, it just wasn't a good experience. Same for the built in reader, it was a bit clunky, not too personalisable, very focused on the incredibly limited feature set the manufacturer considered the direction to go in.

In comparison, the Boox is a proper experience. It's fast, thanks to its modern, yet low power hardware, it runs a stripped down Android so your favourite apps will most likely just work OOTB, and Boox did a great work in ensuring that apps can integrate with their eink control as well as allowing the user to customise the experience. Want to read comics? Comic app runs in high fidelity. Browsing? Enjoy quick scrolling with minimal ghosting, but colours are lower resolution. Reading a book? In BW mode, with quick paging enabled, I need to do a full refresh maybe every 30-40 pages.

Build quality and handling... This also favours the Boox. Kobo decided to forego the uniform front option, so the display is like old ereaders, a bit sunken below the bezels. The Go Color? Smooth surface all around, except for the paging buttons. I do have to say I do prefer the Kobo paging button layout, though, but the power button is much better placed on the Boox.

If stylus input is important, the Kobo has a slight upper edge - it comes with both a drawing and an eraser tip AND a button, whereas the Boox only has the tip and the button on the InkSense pen. Otherwise they're the exact same thing, same precision, resolution, technology really. The Boox stylus is also a good £30 cheaper. For actual notetaking, the Boox wins simply because of the myriad Android handwriting note apps available, should you dislike Boox's offering.

Boox devices also come with built in support for syncing to a bunch of cloud services, so if you end up getting a second Boox device (I'm during their Note 5 Air), all your reading data, books, notes, etc will seamlessly sync AND you can just throw epubs into a Google Drive folder to make them available on device. Or OPDS services, if you're running a tool like Calibre-Web-Automated.

Overall I much prefer the Boox due to its flexibility thanks to Android, and better hardware design.