First hand experience? No. I've handled one and heard plenty about them though.
From what I remember from handling one in a shop, they were a typical polymer framed pistol-not uncomfortable, light, and of course it's an FN, so pretty well made.
Everything I've heard about them is they they are excellent guns to shoot. They have a huge capacity (20), very low recoil (they're firing a .22 caliber round, so that's to be expected), and moderate stopping power (it's a .22 cal round but it's coming out of the barrel at rifle speeds).
Everything about them screams perfect pistol except that ammo. The ammo was designed to defeat body armor, so in their tamed down, hollow point iterations they really don't have much purpose in the civilian world unless you like paying exhorbitant prices for what is basically a .22 Magnum round on steroids.