CDNN is a very reputable place. You can trust them. Be aware though... If you are purchasing a used Sig (where the good deals are) do not expect a flawless finish. You are purchasing a used, most likely police deployed gun, which may not have been babied. If you are concerned, get the hand picked ones, you'll get a better one, but again, it can be hit or miss. Some have gotten ones that were rated a little higher than they should have been, others have gotten perfect ones rated as "good" so just be aware of that. My friend has ordered his last 4 guns from them and I just received one this week from them (new HK USPc .45 LEM) shipped same day I ordered and received 5 days later (shipping is flat fee and via USPS priority, so no over night unless you live closer to texas)
Chris