You can now get IPS screen mods for basically all Game Boy models I think; there are some YouTube channels like Retro Future which cover Game Boy modding fairly extensively.

I had an original purple GBA as a kid and I had a great time on it with ALTTP, Mario Kart, Breath of Fire, and so on, but it having an unlit screen was what eventually killed it for me— I wonder if it's still in a box somewhere in my parents'. There's hardly any point now with having an Odroid portable that plays all the same games, but it'd be neat to see it working again.

The lack of native resolution kills it for me, on a sprite-based console.

Most these days double the resolution in each direction, so you have 4x integer scaling. It’s a different look for sure, but it’s razor sharp and you don’t have shimmering or other scaling artifacts.

I know some of it might be years of training from PC-based indie games with pixel art, but I really like the look of it.

I have it when playing GBA games on my Powkiddy RGB10 (also 480x320 native resolution), and I think it looks great, especially when compared to the 95 PPI display on my other handheld, a New 3DS XL.

Most of these mods require you to destructively alter the original case, which is something some people (including me) would never do, also there are some quality issues in many of these displays.

It would also rub me in the wrong way to use an aftermarket display instead of the one that came with the device, even if it wasn't so destructive.

The IPS V2 fixed the quality issues in the early displays.

I can honestly recommend buying another GBA and modding it. The panel is 4x upsampled, which brings a very cool look to many classic GBA games. It's also a fun experience hacking around in it.

They usually sell with pre-cut replacement cases in fancy colors.

Yeah, but that would mean using an aftermarket case. Some people just want the original non-augmented experience, with all the quirks (also I doubt an IPS mod + case could be any cheaper than just getting an AGS-101).

IPS mods have come down a lot in price and AGS-101s have soared in the aftermarket. American stores sell kits for $50 USD, Chinese-sourced kits are a little cheaper. Add a new case and LCD glass for around $10. A quick eBay search for AGS-101s shows they're going for well over $100.

AGS-101 are so expensive nowadays that yes, it's cheaper to buy a regular SP + new case + IPS screen.

The display was the worst part of the non-SP GBAs; the SP had a much better one. It's the only product I know of with a reflective colour LCD. The colour filters definitely block a lot of the light and even in the best conditions it's barely readable.

Not surprisingly, others came up with plenty of mods to try to remedy it:

https://en.wikipedia.org/wiki/Afterburner_(modification_kit)

Except for use in sunlight.