I'm not one to usually use cases, but I use a Pikachu case for my 3DS (not an LL) that my parents got me when they were there. It's like made of this weird bendable plastic stuff that's very durable and sturdy (dug deeper and I think it's called TPU gel). It fits and feels nicely in my hand. I was able to find the same case online if you'd like to see it:
http://www.play-asia.com/TPU_Cover_for_Nintendo_3DS_Pikachu_L_Version/paOS-13-71-18g-49-en-70-4u7r.html
But you are looking for an LL case I'm asuming. Here's one of the cases I found made of this TPU stuff:
http://www.ebay.com/itm/Official-Licensed-Clear-hard-cover-for-Nintendo-3DS-LL-Yawa-TPU-Nintendo-Game-/121067909023?pt=Video_Games_Accessories&hash=item1c3035af9f
I've also rocked the Kingdom Hearts 3D collector's edition case. It's made of a hard plastic and is no where near as nice as the one I got form Japan. It is very thin and more for show. However, it still fits and feels comfy in my hands, but after a while of playing games, the corners sometimes make my hands hurt.
The cases you linked I don't know about. It's just like a shell and by the looks of it, I think it might have a "fuzzy" or "soft" feel to it. My phone case is like these covers. It works fine, but sometimes falls out of my hands. It also gotten a chip in the corner recently. I keep my phone in my back pocket and so I sit on it many times a day. The case chipped a few days ago on the inside corner. They're good, but I think TPU's better. But if you're just getting the case for the looks, those color cases will be good then!