It's tough to pick, but I suppose I'll go with DS for a few reasons.
Animal Crossing
Mario Kart DS: Super Circuit is one of the few MK games I've barely played, and the controls and physics are too tough for me.
DSi: It unfortunately removes the GBA port, but adds a camera, more processing power, and DSiWare.
3D games: Yeah, 3D titles are still primitive on DS. But they're clearly more sophisticated than the few barely 3D games on GBA.
On the DS and DS Lite you can play GBA games. A GBA+DS combo is probably a better library than GB+GBC+GBA.
It's tough, though. GBA SP is compact and awesome and of course opens up the GB+GBC libraries. For what it's also worth, no DS games make it on my Top 50 of all-time, but Mother 3 and Super Mario Advance 2 (combined with the SNES version of SMW per the list rules) are in my Top 25.
So basically, the higher highs of GBA software are better, but the DS offers more variety.
Lifetime Sales Predictions
Switch: 161 million (was 73 million, then 96 million, then 113 million, then 125 million, then 144 million, then 151 million, then 156 million)
PS5: 122 million (was 105 million, then 115 million) Xbox Series X/S: 38 million (was 60 million, then 67 million, then 57 million. then 48 million. then 40 million)
Switch 2: 120 million (was 116 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
