We still see somewhat old browsers, especially from people using Safari on Apple devices (because IIRC it only updates when you update the whole OS). But it’s a lot better than it used to be thanks to most browser having auto-updates

KOReader is by far better than the crappy stock firmware from Kobo. While the interface is not the prettiest, it still has a lot of advantages :

• it adds the ability to browse the filesystem (how do people use an e-reader without folders ?)
• loading medium to large PDFs takes ages in kobo’s stock UI, while it’s almost instant in koreader
• there are a bunch of plugins you can add to koreader

While I really hate Kobo’s stock UI, I still recommend getting one if you like truly owning your hardware. It’s really easy to enable ssh access and then it’s just regular Linux. It’s even possible to run an X server and launch Linux graphical apps on the e-ink display (not quite usable though)