It has an amazing library, and even with the slew of new devices coming out I still feel that original hardware is the absolute best way to play that library.

IMO, the biggest flaw with the new handhelds is that they all use capacitive touchscreens since resistive just isn’t manufactured anymore. Touchscreen-centric DS and 3DS games were designed with stylus use in mind, and capacitive styluses kind of suck for that. This applies moreso to the DS library, not as many 3DS games are stylus-driven, but there are some and if you want to play them you will have a much better experience on original hardware. No other handhelds offer the 3DS’s glasses-free 3D either, which I know not everyone cares about to begin with, but I personally do like it, so it’s another factor to keep in mind that you’ll miss out on.

If you want to play online, Pretendo Network only supports original hardware. Real consoles have a unique ID that is signed, and if you misbehave they will ban you from the network. But emulators can freely change and spoof IDs to circumvent bans, so they have to just not be allowed on the network to begin with. Pretendo is still in its infancy anyway, not many games are supported and there isn’t much of a playerbase, but if you care about it then it’s something to be aware of.

Also note that if you want to play original DS games, I prefer an original DSi, or DS Lite due to the screen resolution. While the 3DS is backwards compatible, the screen resolution is not an integer scale, so it’ll look awful if you scale to fullscreen or tiny if you keep it original size. The latter is less bad on an XL, but you’re better off just rocking fully original hardware. I prefer DSi for softmodding and the DSiWare library, but if you really need the GBA slot too go with the Lite. GBA is much more easily emulatable elsewhere anyway though, unless you’re specifically looking to play DS games with slot-2 interactions.

But if you don’t already own any of these systems, I don’t think the absurd prices they’re going for right now are fair. Although the emulator handhelds do have some flaws, they’re ultimately easier to get a hold of now, and they do have pros when it comes to an all-in-one device that’ll also emulate other platforms. N3DS has some some decent emulator support of its own, but is even more expensive, while O3DS can’t play much more than its own library.

So every device has its pros and cons, figure out what your use case is and how much you’re willing to spend. Do you want the best possible experience for 3DS and/or DS games specifically, or would you rather have a jack-of-all-trades device that does everything else? I love my old DSi and 3DS because I already own them, but I don’t think I’d pay full price for them today.