The early adopters of the FNS-9 must be pissed to know that these rather unimpressive pistols (in my opinion anyway) are now selling for under $400.
I bought a brand new FNS9 with stainless slide, night sites, and manual safety for $400 from MGW (plus $40 shipping) over a year ago. I thought I got a great deal. Gun shot ok but offered nothing special. The polymer of the FN pistols is cheap at best. Got rid of that thing like a hot rock.....and I still took a bath due to my LGS not being able to move the new ones they had.
I prefer hammer fired over striker fired, so I prefer the FNX. I feel the better trigger on the FNX (when in single action) has more of an impact on accuracy than the slightly less felt recoil of the FNS. It is 9mm, so recoil is very light on either model.
The biggest difference between the two is if you want the DA/SA of the FNX or just the DA of the FNS. People either like or dislike the single action, so that is not something someone can answer for you. My suggestion is to try to find a range that has the models as rentals (unless you have buddies with either) and try them out.
Complaints against the FNS mainly involve the trigger (which isn't horrible no matter what anyone will tell you) having too stiff a pull (most come in between 5 and 6 pounds with a consistent pull) though being intended as a service gun, is acceptable. A hair trigger on something a LEO might be pointing at someone is never a good idea.
Complaints against the FNX are that it has a higher bore axis (not much but noticeable) so it has more muzzle flip than it's striker-fired brother. Since hammer-fired means a bulkier slide and more weight at the back, this is expected though it's still a sweet shooting firearm. Also, a great many have complained about the placement of the safety, so make sure you actually not only get hands-on with one before you purchase, but also get range time to see if you're one of the guys who takes a safety to the back of the thumb.
i had an FNX40 and FNX45 and i still have my FNP9 (for nostalgic reasons).
striker fired all the way. The people that push DA/SA guns are people that shoot at the range and never from a holster. i don't care how much you practice. Your first shot from ANY DA/SA gun is always the hardest. and it's also the most important. using a DA/SA gun just makes life harder when it doesn't need to be.