I have one.
I have a black New 3DS XL and previously to that i had a standard 3DS.
I must say that i'm pretty happy with it. Its a good upgrade, the 3D is stable and stays in focus, its more comfortable to hold too. It has clicking points so that you can open it to the required amount depending on how you're sitting or holding it and have it stay that way.
Mine came with its own memory card which is actually quite a size and that was free already inside of the console. The download speeds are fantastic, i've gotten full games from the eShop within minutes and downloads for virtual console games take seconds whereas with the standard 3DS it felt like it took forever.
It doesn't make the games look ugly, which is what i was worried about considering it had a larger screen, the new buttons feel fine to get to and use and the new camera stick nub-thing feels fine too, its quite fun to use actually. Plus it has amiibo functionality so that'll save you having to fork out money for an adapter for the standard 3DS. I've used the amiibo a fair few times now for Smash and it doesn't slow the game down at all, its quick to recognise them just like it is on the wiiU
I say its a decent upgrade, i was thinking about getting an XL so im glad i waited, its the best of both worlds, an XL which does downloads faster, has good memory, has some hardware features like the clicking points, it isnt as jagged around the edges as the standard 3Ds and has good 3D. If you have only had a standard 3DS then i say its good investment to upgrade.