I have a Red & Black 3DS XL that have a broken speaker and a cracked hinge, and my current Black 3DS XL that functions relatively well. I plan to sell it whenever I get a North American standard black New 3DS model in my country.
I also have a few Japanese 3DS models. First off is the Ice White 3DS, which is currently discontinued. It works very well outside of Animal Crossing: New Leaf, which often experienced crashes.
Another system I own for that region is a Nintendo 3DS LL Luigi 30th Anniversary Pack. Functions 100% of time, but the right hinge is very slightly cracked.
And last but not least is the standard white New 3DS model, which currently has the Yoshi coverplates (No. 004) attached to it. This my personal best 3DS model and the only one I'm currently using.
I got the pink and white since there was no solid white (or mint and white /tear) and put a skin on it. I might get a regular new 3DS if it gets any exclusive games that I need in my life.
I don't plan on getting the 'new' 3DS anytime soon but if I do, it will likely be the one that closest resembles my current one (since I like the color)