I would go with the FNP-9, but it's a tough call. I own both the FNP-9 and the Beretta PX4 Storm and they're both great. Each is among the best in the breed, including several of the SIGs, but you can't overlook three magazines that come with the FN handguns.
I bought the FNP-9 first after trying a number of different pistols. The only pistols I liked as much as the FN were the Beretta and the SIG Sauer P226. The SIG was hundreds of dollars more expensive and the Beretta had just two magazines and was about $50.00 more expensive. I didn't hold out for the manual safety USG because I am quite happy with the security the decocker offers. It drops the hammer to a "half-cock" position to prevent UDs while keeping the gun ready to fire with just a full pull of the trigger.
I bought the PX4 Storm for two reasons: First, to go with the CX4 carbine I had bought to join the Space Marines. All kidding aside, I like the PX4 as much as I like the FNP. I did deliberately get the Model F because I like a real hammer that I can thumb back if I wish. The second reason is that Academy had a super price of $519, which was better than I found anywhere, including online. I did augment the magazine collection and now have four 17-round magazines and two-20-round magazines that I can use in either gun.
Between the three guns, I can load all the magazines, add a round in the chamber and be able to fire 159 rounds without reloading.
BTW: I went with 9mm because of ammunition. When I bought the FN, ammo was in short supply and 9mm was both available more often and less expensive the .40 S&W. IMHO, 9mm is just about as good as .40 S&W as a S/D round and more pleasant to shoot.
Both guns are fun to shoot, accurate, easy to strip for cleaning, feel great in the hand, come with various grip inserts to allow a bit of custom-fitting, if desired.
Some complain about the slide-mounted safety on the PX4, but it doesn't bother me. The majority of automatic pistols I have owned had similar safeties and the one on the PX4 is smooth and easy to disengage with my thumb.
The PX4 has a slight advantage when it comes to selection of ready-made holsters. You can get good holsters for either gun, but when it comes to holsters like the Blackhawk CQC or Fobus, you can't yet get one for the FNP. Safariland and Bianchi do have holsters for the FN and either gun will ride in an Uncle Mike's nylon holster.
Both the FN or the Beretta are good choices. The best suggestion I can offer is to see which one feels best in your own hands and go with that one. Either way, you wind up with a really nice pistol.