re: If you had to choose: Walther PPQ, HK P30 LEM v1, HK VP9, sig 226

Well, that is basically a hammer fired vs. striker fired comparison. So that's your first choice. I'm really into hammer fired right now so i would move on to the sig vs. HK. I really love HK LEM trigger. Its reset is not bad. The sig is also great and has a great SA and DA trigger. I've heard sig's DAK (DA only) trigger sucks. Be sure to get the SRT version and I also have the reduced reach version for smaller hands on a bulky grip. Since you listed two striker fired, i would recommend the HK. I love that trigger. However, the sig is really great too and as an all steel tank of a pistol, its a real value holder.