I was checking this company's products for the DSi(XL) before the 3DS launched, only hoping they would make a case for the 3DS. The customers reviews are all 5 out of 5, and the quality seems to be very high. Most people will be happy with the standard clear/aluminum cases, but I don't mind spending the extra money for a high quality accessory. I'm definitely getting one of these cases.
One thing I can say is that I bought the aluminum case with the rubber flap over the hinge, and I had to modify it to fit my needs. I pulled the rubber flap and metal rods out, sawed off the two plastic nubs that held the rod on the bottom shell, and filed them down so my fingers wouldn't hit them while playing. This CM4 case stops before the hinge, doesn't interrupt the L/R button area (for those who rest their fingers across the top of the 3DS while playing), and looks thin enough to not make accessing the stylus and SD card a pain.