I think NP3 will run you $225-250 on a handgun, plus shipping there and back. Spendy proposition. I had Robar do a Colt 1911 .45 in NP3, and they did JACK SHIT prep work on it. For that amount of money they should be doing some bead blasting or polishing beyond just taking off the old finish. NP3 is very slippery, probably too slippery for a gun like a Beretta with no checkering on the frontstrap. I didn't like it, ended up selling the gun. You can have your gun hard-chromed by Accurate Plating and Weaponry in Florida or by Mahovsky's Metalife for quite a bit less than NP3. APW does more prep work, Metalife is a little better finish (their chrome bonds better to the gun, seems to be more rust resistant). Having your Beretta Metalifed would run you $159, including return shipping. Quite a savings over NP3. I think hard chrome looks better, myself. The only problem with metallic finishes like NP3 and hard chrome with a standard Beretta is that you end up with a silver front sight.
NP3 and especially hard chrome will WAY outlast any of the black finishes. Also, the mating surfaces on a chromed gun will polish over time and make it run smoother- I had a chromed Commander that ran much smoother than when it was blued, once the chrome polished up.
My vote is for one of the hard chrome finishes. I think Robar is overpriced and overrated.