If you plan on pocket carry IMO the extra width and weight are critical with the LC9 thinner and lighter, but if you plan on IWB carry the Sig is interesting.Forgive me for exceeding the parameters of the question, but I have been window shopping for a small 9mm, preferably hammer-fired and looked at both the LC9 and PF9. I've been leaning toward Ruger until another, a bit more expensive pistol caught my attention. Consider the Sig Sauer P290RS. Costs a bit more in the mid 4's I understand but come with two magazines, a six and an eight round. Is hammer fired, real DAO, with re-strike capability, no magazine disconnect, no internal lock, no huge LCI, has night sights, stainless slide (either natural or nitron finished). The inserts in the polymer frame are steel, not aluminum, which does make the pistol a bit heavier at 20 ounces or so but arguably stronger, IMO. It is shorter than the Ruger in height and length but is a tad thicker.
I have not been able to examine one yet but I'm not going to buy any small 9mm "pocket pistol" until I can. And I am a long time Ruger fan.
For me second strike capability is not important and would not be used in a self defence siduation. Most police departments teach officers to do a tap rack if there is an FTF.