I'm pretty sure people didn't buy a 3DS just for OoT 3D. In fact, the main reason I got the 3DS was because of Kid Icarus, 3DS OoT, I knew they'd be making a new Mario Kart, and then when I saw the list of games coming out in the future, I decided to get one early while I had the money to spend.
All in all, you're gonna' meet a LOT of people on here telling you it's not worth it, just play it on the N64 or on the VC, and who cares about graphics, it's the gameplay. As much as I agree with that, I mostly paid for PORTABLE OoT, as I love playing games on the bus, on the way to work, etc, and playing OoT on the way to work is just fun as fuck, haha. At the same time, I wont lie, it does look nicer and smoother / crisper and I find it's just refreshing to play a portable classic and have it look nice. And yeah, I'm a gimmick slut, so I think the 3D is ballin', haha.