I am not going to get into the "Why-get-a-380-when-there-are-small-9mm/40-caliber-pistols-available?", or the "stopping power" issue. The reason is simple: On the forums, folks asking about specific .380 pistols sometimes put in the request not to go into the 9mm/.40 options, stating that for whatever reasons, they are going with a 380-caliber handgun...and are routinely ignored with the usual Caliber A vs. Calber B arguments which sometimes results in the threads' never getting around to answering the original questions! The thread gets "hijacked" by well-meaning posters arguing over caliber rather than answering the questions originally asked!
With that caveat, let's see what we might see...
Bbl: 3.6" w/1:10" twist
Weight: (aluminum frame) 18.5 ounces (all stainless) 23.6 ounces. (Both of these weights do not include magazines.)
Magazine Capacity: 7
Magazine Weight (empty): 1.4-oz blued and 1.6 oz-stainless
Internal Firing Pin Safety: Yes
Magazine Disconnect: No
Grips: Black synthetic
Trigger Pull: 10-lbs.(DA) 4.4-lbs (SA)
Decocking Lever: Yes
External Thumb Safety: No
In addition, the gun is available in blue, stainless and two-tone finishes.
The Beretta 85F has proven itself reliable as were its predecessors. The F-Series have the hooked "combat trigger guard. I prefer the more traditional rounded ones.
Bbl: 3.81" w/1:10" twist (actually 9.84 but 10" is close enough)
Magazine Capacity: 8 shots
Grips: Black, synthetic
Decocking Lever: Yes
External Thumb Safety: Yes, ambidextrous (Pushing these upward with the pistol cocked will safely decock the hammer and then the pistol cannot be fired until they are pushed downward (ala 1911) to disengage.
Some of the discontinued "B" and "BB" models were offered in either blue or nickle finishes. The current "F" models are available in the dark Brunitron finish which protects against corrosion.
Both the SIG-Sauer and the Beretta can be had with wooden stocks if desired. Both the front and rear grip straps on the Model 85 are serrated. These are smooth on the P232.
The SIG-Sauer P232 can be had in the lightweight aluminum frame/blue slide version or the heavier all-stainless "SL" version. The Beretta is offered only with the lighter aluminum alloy frame.
I do not have information on the DA/SA trigger pulls on the Beretta Model 85F, but to me it is similar to the SIG-Sauer. I do not find enough difference to be of any consequence. If it is of any importance, the P232's trigger face is smooth while the Beretta's is grooved and has a trigger stop. (I find neither trigger face or pull superior to the other in actual use on these pistols.)
The Beretta with its smaller serrated flats seems to generate more complaints about difficulties in racking the slide than the SIG-Sauer's if that is an issue. I find the SIG-Sauer easier to rack, but don't find either a problem. This might not be the case with some of our older folks or those with weaker hands or arms.
While both are "straight blowback" designs, the SIG-Sauer's bbl is fixed to the frame. The Beretta's is not; it is removable during the field-stripping process. That said, I have not been able to determine any accuracy degredation in the Beretta due to its "non-fixed" barrel. It is simply not an issue in my view. Neither is the slight difference in barrel length between the two. Average velocites with factory ammunition have proven very similar between these two little autos.
I've never shot a Beretta Model 84 or 85 that didn't mimick the Walther PP series in that shots hit about 1 1/2 to 2" high for me at ranges of 15 yards or more. (Most folks will not be interested in shooting these "pocket guns" at great distances and at closer ranges, the sights are "on" close enough in my experience.) Unlike shooting the Walthers, I do not suffer either slide or hammer bite with the Beretta or the SIG-Sauer.
For me, the SIG-Sauer P232's in .380 hit "dead on" for me at ranges from arm's length to about 25 yards or so. I much prefer the P232's sight picture to the Beretta's, but that might not be an issue for a pistol intended for close-in use and that was never intended as a formal match pistol.
The following is based on a relatively small number of handguns but I find either the 232 or the Cheetah to be very reliable with ball and JHP ammunition. (Most of the earlier P230's I shot were fine with ball and some were alright with JHP's but not all. I have not shot any Beretta Model 84 or 85 in any version that wasn't reliable with any and all ammunition. I think SIG-Sauer was aware of this issue because while I only own one P232, it's been 100% reliable with all FMJ and JHP ammo as have those owned by other shooters I know.)
If I shoot over about 200 rounds of standard-power .380 in a session with the P232, I do notice a couple of little "wear" areas where the edges of the tang rub my hand. None of this occurs for me with the Berettas in either the M84 or 85 versions.
Which is best? I flat do not know. Both are quality firearms. Between the two, I think I prefer the SIG-Sauer P232 but I don't intend to sell my Beretta 85F either!
I find either easy to shoot accurately in double-action mode and both are a piece-of-cake in single-action. I do not notice any difference in felt recoil between the two.
Sweeping "off" the thumb safety is easily done and comfortable for the Beretta, but it is perfectly safe to carry with the thumb safety disengaged as it has an internal firing pin safety like the P232. Some will opt for the gun having the external safety as it not only offers perhaps another level of safety but might prevent an attacker or unauthorized user from immediately grabbing and firing the pistol. If this is a major concern for you, the Beretta is the way to go as the P232 offers no such external safety; it is a "point-and-pull" design.
Both offer an external slide release.
The Beretta has the magazine release at the rear of the trigger guard like the 1911-pattern pistols, Hi Powers, etc. The SIG-Sauer's is a bottom-release design ala the Makarov and other European designs. (The Model 85F's push-button magazine release is not ambidextrous.)
While the Beretta's is probably quicker in the event of a speed magazine change, the SIG-Sauer's is considered less like to inadvertently release the magazine as might happen were the pistol sat on or carried tightly against the body. Again, what is actually "important" will be up to the individual buyer's perceptions.
I seldom carry pistols of this genre but were I depending upon a .380 for "serious purposes", I would absolutely not doubt the mechanical ability of either of these, though between the two, I would probably go with the P232, simply because I much prefer its sight picture and that POA matches POI for me better than the Beretta. (It is possible that this will not hold true for all or that it just won't be an issue for many.)
Again, speaking only for myself, I doubt that I'd pick the heavier all-stainless P232 and in my admittedly subjective observations, I don't find either the aluminum-framed P232 or Model 85 difficult to carry nor do I find one to have a "real world" advantage over the other in this regard. (Were I concerned with rust and corrosion, I'd go with the Brunitron finish on the Beretta.)
Hand-cycling ammunition through both guns seems to result in more positive ejection of the cartridges with the Beretta than the SIG-Sauer but in actual firing, both fling the fired cases well away from the shooter. Both use external, pivoting extractors and I've not noted one being better or tougher than the other.
Unlike the 1911, there is not a literal cottage industry of aftermarket parts for either of these well-made pistols, but both remain in production and OEM parts as well as aftermarket grips and recoil springs are available, as are extra single-stack magazines.
As mentioned earlier, I think that the choice between one or the other of these two pistols is not a choice between quality but between the guns' individual features as well as the buyer's subjective preferences. Either of these guns are well-made and quality firearms in my opinion.