Is it worth getting? Yes. But...
New Nintendo 3DS is a wonderful machine, and arguably how the 3DS should have been done first time round. The new super-stable 3D is wonderful, the extra navigation and download speed is very welcome and the extra control stick should make a lot of difference to games with 3D cameras. But that new C-stick nub is very strange, especially considering the circle pad on the left is pretty darn perfect.
If you don't already own a 3DS, then you should absolutely get a New 3DS. Right now. And of the two, the smaller one (not available in North America) is the one I'd recommend, thanks to the more pixel-dense display than the XL, it's more compact feel and the fact that it's lighter to gold for long sessions. Here's hoping the New 3DS joins its big brother in NA soon.
As for whether you should upgrade from your existing 3DS, there's no immediate rush. You'll notice the improvements, but until there's something you absolutely have to play that only works on New 3DS, the old one is just fine. Amiibos aren't integral to Nintendo games just yet, either. When New 3DS-exclusive games like Xenoblade Chronicles come out, it may become essential. As it is, it's simply the best handheld console you can buy. I don't need to tell you that's a big deal.
And if you're looking for more, check out The 25 best 3DS games and 10 bold Nintendo predictions for 2015.