- Faster processor, meaning certain retail titles run faster (Super Smash Brothers).
- A couple of decent exclusives (Xenoblade Chronicles 3D, Binding of Isaac, and the official SNES Emulator on the eShop).
- Better 3D that's actually a lot more usable.
- Amiibo support if you have any games that take advantage of them.
- microSD Management comes built in, but this might be an invalid point since the original models can have it if you can install unofficial CIAs.
- Better build quality than the original small model I upgraded from. I skipped over the 3DS XL, so I can't really compare it.
- Best in terms of homebrew. Not only do we have NTR Video streaming, but Retroarch 3DS emulates a lot of systems quite nicely on the New 3DS with little to no hiccups. Compare this to the original models where only a couple of emulators run nicely with kernel access. You can also configure the New 3DS' extra horse power in Luma3DS (AuReiNAND) to always be enabled, which can actually make a lot of games run much more smoothly. For instance, Rayman 3D. There are some other nice homebrew titles that take advantage of the New 3DS' specs, so there's another nice benefit right there.
The only real downside is the somewhat inconvenient microSD card location. It's behind the backplate, and needs to be removed if you need to access it at any point. Assuming your friend is going to try to install arm9loaderhax, he'll have to remove this a couple of times if memory serves. Once he has a good setup though he should just be able to rely on microSD Management for his needs.