the Beretta 84 is a fine gun.
It is a bit big for a .380...but that makes for an easier shooting gun.
It is a blowback operated gun...so the recoil spring is a bit tougher to absorb the recoil of the slide...some people do not like retracting the slide on a Beretta 84/85 series. As a result Beretta also offered a 86 model with a tip up barrel that allowed someone to load the pistol without having to retract the slide.
They also made a slim line version with a single stack mag...the Beretta 85. I have two of these...love them. They fit my hand like a glove. Easy to shoot very well....and very reliable gins.
which model 84??? There are a number of models 84, 84B, 84BB, 84F, 84FS
I know a lot of people will comment about the weight versus size and caliber of the gun. There are 9mm's that are smaller than the Beretta 84 such as the Glock 26, etc...when I had my first Beretta 85's I sold them for that reason...shifted to a Glock. That being said...the Beretta feels great in the hand...which is why I went back to the Beretta 85F. It is not my main carry gun....but I would not hesitate to carry it as long as you use a good self defense round with it. Mine frequently pulls night stand duty