I really like my security six, it's a 4 inch though. I do love the weight and balance of it whereas the GP felt a little big in the grip frame, but that's just my personal feelings and everyone will be different.
I'd pull the pin on it if you can, and try to talk them down a bit. I would have paid that for mine, but ended up getting it much cheaper.
I don't really have any complaints, I do like how easy it is to field strip the gun, the GP wasn't mine so I never got to take it apart, but the security six was intended to be taken apart with a coin. To me that's a real plus for a shtf type scenario.
I guess I do have one complaint, but it isn't much of one... there aren't many options out there for paddle holsters or replacement grips for the security six, if there are, I haven't found them yet. I would really like a paddle holster for mine just because it's easier for carry around the farm...