Had my New 3DS for a few weeks now (ambassador edition) and you know what, I think, it's my favourite Nintendo handheld to date.
So I had an original 3DS (still have it, I managed to get the system two days early than EU launch) which I replaced with an XL due to the hand cramps it gave me. I had some reservations about going back to the smaller unit but, I have had no issues with hand cramps what so ever. In fact, I'd go on to say that this is the perfect size for my hands (just average hands I guess) and I find the system a joy to play.
The new 3D is actually pretty effective, I am not a big 3D fan, I don't often use it but when I have I have been impressed with the stability of it. The graphics look much nicer on this smaller screen than the larger XL.
Furthermore, I have played the 3DS a lot more since getting the system despite having no new games to play! I have played a lot more Animal Crossing and Pokemon X, just because of this system. The speed of the system is noticeably quicker when doing anything on MiiVerse or the eShop. The system feels well built and the faceplates fit much better than I thought, I originally thought they may feel a little flimsy, with gapes on the sides because the top plate just clips into place but no, they feel really nice.
Feel free to ask any specific questions.