I went ahead and installed the VQ hammer and extractor on my 597 Magnum before even firing a shot through it 'stock' (I have the original Remington parts tucked away in a bag somewhere 'brand new/never been used').
Although I can't say how the rifle now compares to the way it was prior to wearing the VQ parts (since it was never fired without them), the trigger pull is certainly light and crisp. As far as the VQ extractor is concerned, I've probably fired a thousand or more rounds (CCI MaxiMag) through the rifle and have yet to experience a single FTE (or FTF, for that matter) ...none.
Great rifle that regularly shoots single-hole groups at 25 yards and sub-inch groups from 50 yards (I haven't spent much time with it at 100 yards yet ...but it is a magnum, so I'm sure that I'll be giving it a try).