So yeah, I went to the Nintendo 3DS event in London on Saturday, and had a good play with some games. Overall impression is that it is a pretty impressive piece of kit.
The hardware felt lovely to hold. It felt more svelte and sturdier than a DS Lite. The Slidepad felt great, and accurate. The buttons just beneath the screen are not completely flush as they appear, but when you run your finger over it, there is a small bump that clicks when you press it in, i.e, the Start button. The whole thing appears a lot smaller than what it seems on camera or in media. I also thought the screen could have been bigger. As far as the 3D on the device is concerned, you had to find a comfortable 'sweet spot', but once you did, it felt very natural, and there was no strain. If you move the 3DS about 5cm away from your direct field of vision, then you get the 'double-vision' effect.
Games I thought were outstanding on the 3DS were:
http://www.youtube.com/watch?v=N5AH2FoE5L0
Zelda: Ocarina of time - This looked gorgeous!! Check the video above, filmed from the London event! The models, animations and 3D effect were brilliant, and contrary to what was said earlier in this thread, I disagree about it being disappointing. It was probably the most impressive game I played on the day, very bright, 60fps, sharp and colourful. I was never drawn into playing the Original that much, but once I started this, I found it hard to put down, and was made to after the 'Thank you for playing' demo limit message popped up on the screen. The game is A LOT better than I expected.
Super Street Fighter IV: WOW, I really never expected to see anything this good on the 3DS, but I was blown away with how crisp is looked, especially with the 3D effect switched on all the way. The depth slider all the way up adds extra details IMO. The animation is fluid, and everything seems here! The only thing I noticed were that backgrounds are static. I was taken by surprise at one point, when someone managed to join into the game who was standing close to me at the event. It was so seemless and fast joining that we didn't even notice until we both reached the character select screen, and our 3DS's synchronized. I played in Dynamic mode, which gives an pseudo over the shoulder view, and the opponent is in the distance, and he played classic side-by-side. Next to Zelda, I want this game bad!
Resident Evil: Mercenaries - This looked great, the 3D effect wasn't as impressive, but the game handled and played very well. Feels weird playing a 3rd person shooter on something that feels like a DSLite! I enjoyed it though, and can see it being addictive in multiplayer.
Ridge Racer - Again, contrary to earlier opinion, I quite enjoyed this, especially with the 3D effect switched all the way up. It makes the track and scenery seem really far away, and a better sensation of speed. They also have nitro boosts in the game. What I don't like is that they still have the same physics as the very first ridge racer, so when you spin out, your car swerves side to side unrealistically.
Face Raiders! - This was one of the Augmented Reality games on show, so much fun! It is a silly same where you take a picture of your head, and it gets superimposed on other peoples bodies as you swivel the camera around. I like the way that the eyes and mouth are animated in 3D when you shoot the head, or when it goads you on.#
AR Card game: There was an augmented reality game where a card was put on the table with a ? block. You hold the 3DS about 35cm away, and things start coming out of the block which you start shooting at. I like how you can go 'around' the objects in real time, and shoot stuff. A dragon sprouts out of the block eventually and you can walk all the way around it shooting off parts of its body.
Biggest disappointment: Rabid Rabbits - this game was a shit platformer, really shit! It was weird seeing this on display when everything else was so good!
I have been convinced, and for me now the 3DS will be a day one purchase!