Sorry, I can't cast a vote because although the 228 and 229 are physically the same, you are talking about two totally different calibers.
Now, if you are looking for a 9mm, I'd recommend the 228. It's lighter and most of the 229's weight is up in the SS slide making it top heavy, IMHO.
You will get suggestions by some to get the 229 in .40 or .357 because all you have to do is buy another Sig barrel (opposite to the one you have) and the gun will interchange between the two. After that, a 9mm conversion barrel from someone like BarSto will give you all three calibers out of one platform. Personally, I wouldn't do it. But, you have that option.
Again, both guns feel almost exactly the same. So, go with the caliber you want the most.
-Red-