The FNS experience at my former agency does leave me with a bitter taste in my mouth. This was compounded by FN representatives at a long ago promotional gig trying to convince me that all the California SWAT teams and the FDLE special operations teams were adopting the FN5.7. This was exacerbated by the cool guy firearms instructors trying to push me out of the program desperate to choose a pistol that, #1, the county police did not carry abd, #2, that we'd be really cool because almost no other agency carried the FNS.
That bile spewed, FN clearly makes some quality firearms. I will also comment that FN was quick to admit and attempt to correct the issues with our weapons, FN replaced barrels and magazines with no issues. That resolved most of the issues. Many of the problems stemmed from pistol-mounted lights. Ironically enough, our new cool guy firearms training coordinator had decided PML's would be mandated with our new pistols.That policy didn't last long.
While I haven't shot the FN 509, it seems better than the FNS. For the sake of LAPD officers, I hope it is.
I will remark that, when we realized our FNS-9's were garbage. I didn't send a department-wide email suggesting we ask FN to trade our FNS-9's for Hi-Powers.