Tried them, gave them up.
Owned an FN 509 Compact Tactical. GREAT gun. VERY high quality. Already set up for multiple red dot mount types, suppressor ready threaded barrel and suppressor height sights. Nice grip, ready for a light, compact, good mag capacity. Multiple capacity mags available.
That said, I like FN pistols a lot! I'd probably have done better with the compact 509 with standard height sights. Yet...damn it was uncomfortable to carry.
Went back to my Gen 3 19. Simplicity is a thing; mags are (not that I care, I can afford them,) half the cost. And, it's and more comfortable to carry W/O the strapped on weight and angles. Accessories and holsters...MUCH more available.
Really made me a nonbeliever in all the crap you're made to beleive you need to strap to a handgun theses day. Wasn't for me.
Have seen the elephant, more than once, don't need the assistance.