I'm looking into buying my first handgun right now as well. I think I've narrowed it down to either the Sig P229 or the XD. Here are my main considerations:
1. Shoot-ability. I have shot the 229 (but not the XD), and the DA on the first pull was quite long and heavy (sts). The trigger on the XD felt lighter and shorter in the store, which would make multiple shots easier to get off rapidly if need be I think. That being said, I got good groupings with the 229. The 229 was pretty heavy though.
2. Reliability. I've seen the tests for the Sig and am impressed, but I hear the XD is just as good. Basically to use this gun for home defense it must go bang every time. I want it to last a long time, will rust be a problem with either? I also feel like the Sig is a simpler gun, I understand it all how it works, ect. I am not as clear on the XD with SA only and the grip safety, and if/how to maintain them.
3. I was pretty set on the .40 but now am leaning toward the 9 mil, but I go back and forth. Even though it has greater stopping power will I be able to handle it as well, and over multiple shots? Also 9 mil is cheaper... (yes I do want to fire at the range often enough to stay proficient)
Any other considerations or comments would be greatly appreciated, or if I am way off base let me know. Thanks for the advice!