I carry Sigs everyday. My only complaint is I have to polish the outer barrel chamber where the finish wears the first few shots. I have yet to have them fail me, and most likely in my lifetime won't.
I tend to like the little extra pride in fit and finish Hk does. I have seen a stock barreled Hk94 with over 200,000 rounds and still shoots great. Hk, IMHO makes the very best pistols and rifles that are mass produced. That being said Sig, to me could not be any closer in the running. I have been comparing the Sig 516 and the Hk 416. The Hk has far better barrel life but to be honest the Sig is the best AR bang for the buck.. So Sig or Hk, potatoes, patatoes... You will most likely be happy with either or. There handguns are well made..