I have had many transactions with CDNN and never a problem. Very fast turn arounds from order to ship. Since I'm "local", same state, the stuff is usually at my door the day after shipping.
I bought my 3" Model 65 from them. It needed a new strain screw because whoever had it before me thought he was a "gunsmith". Other than that, it was as good as or better than advertised.
I wish I'd bought one of their .40 S&W Browning Hi Powers when I had the chance.
I wouldn't hesitate to deal with them again, and highly recommend them.
I have bought accessories from them with no problem. Quick order processing and shipment. When I need accessories I check there, Midway and Cheaper Than Dirt for availability and price.
I picked up some 4006 mags from them several months ago. Easy to deal with and fast mailing. I was impressed with them and will buy from them again, whenever they have something I think I need.