I think the New 3DS will be better in general. I would need to try it myself, though. Some disadvantages I see from the circle pad Pro:
1) It makes the 3DS even bulkier, especially if you have an XL.
2) It is a bit pricy, especially the XL version: 21€.
3) It needs its own battery.
I think Nintendo should have launched this 3DS model at first, at least the one with the button upgrades. I still don't like that they are going to fragment the user base by making a beefier 3DS at the middle of the generation, unless the games they put are ports from the Wii that I can find easily and I don't care because I have a WiiU.
The PS Vita got it right to provide a complete set of buttons at first. This update wouldn't have been necessary if Nintendo had released a 3DS like this before. The circle pad pro was a quick fix, this is what the 3DS should have looked like initially.







