I'm sort of in the same boat with the 3DS. Heck, I'm in the same boat with the DS.
Whenever it was time to travel or time to sit in line or time to wait for a turn, I grabbed my PSP instead of my DS. Similarly, I now prefer to grab the Vita instead of the 3DS.
When the clamshell DS was first released, I thought it was ridiculous. None of the games seemed fun. I think what eventually lead me to getting one was Castlevania: Portrait of Ruin and the ability to play GBA games on it. Whereas, I got a PSP around the time it was first released.
I'll admit I picked up a 3DS around launch so I could participate in the Ambassador Program, but I never bought a 3DS title until Tales of the Abyss. I spent more time playing that Baby Mario game instead of an actual 3DS title. But, when I got a Vita, I picked up Shinobido 2 and made a bunch of pre-orders for upcoming Vita titles like Ys.
*shrug* After the GBA, I felt that the portable war was in Sony's favor. Most will disagree with me, but I've gotten much more mileage from my PSP and Vita in comparison to my DS and 3DS.