Great pistols. Not sure why there are so many for sale. The only thing, more of a training issue, is going from the double to single action. Triggers can be improved with parts change. I have had two, along with P228 and 220 in da/sa. There are also .22cal. conversions for them to cut down on ammo costs. I don't have any experience with the Norinco copies other than handling one. You do get what you pay for, and I'm sure lots of people swear by them but of course the fit and finish is not there.
If you are more inclined towards the same trigger press each time, then check out the 320. There was an issue early on with possible drop fires, but that was fixed under recall and all pistols incorporate the new fire control units. The triggers are good with short take up and reset, various models and price points, and the ability to fit the gun to your hand better with cheap grip frames is a bonus.
Never had an issue with any of the Sig products and have used them a lot.
Good luck with your decision.
P.