[iMagUdspEllr]

1) This is a matter of which type of action/trigger-type you prefer. Do you want a consistent 5.5 lb trigger pull or a 10 lb DA pull followed by 4.5 lb SA trigger pulls? I, personally, like consistency. Its important for building muscle memory. Not to mention it is much easier for people to shoot when they aren't struggling with a 10 lb DA trigger (for the first shot only... but its still your first shot).

2)I think you should buy either gun new. No reason to buy a used one just to discover the previous owner screwed something up on the pistol (whether it is cosmetic or not).

3)Glock 19 because Glocks are one of the most reliable guns ever made. That isn't to say that Sigs aren't reliable. They definitely are. They just cost double. The Sig is heavier so it will have less recoil, though.

4) I don't know why you are comparing the P226 to th G19. You should be comparing the P229 to the G19. I would choose the Enhanced Elite P229(6).

5)I haven't seen any data that suggests one is definitely more accurate than the other. The P226 has a longer sight radius so it will be easier for you to be accurate with it (but then you should be comparing it to a G17 at that point). The P226/9 are all steel so you will be able to hold the pistol steadier (when things are heavier they tend to not move around as much). The single-action trigger on the P226/9 is very nice and will make it easier to be accurate with also (don't forget that you have to deal with the 10 lb double-action trigger first).

Note that all of these properties just make it easier for you to do what you are supposed to be doing. There isn't anything that indicates that the actual barrels are more or less capable of making tight groups with either pistol.

6) The Sig would be worth the extra money for the reasons I have stated if it weren't for being a DA/SA gun. But, that is just my personal bias. Having to master two different trigger pulls and one of them being a 10 lb DA trigger pull for double the price does not appeal to me. Many people don't care, though. Many people have either mastered the DA trigger pull or are content with ripping through that first trigger pull since ultimate accuracy isn't paramount at common self-defense distances (I prefer to be as accurate as possible with every shot... just me, though).