There are only two versions of the P97: (1) Decocker; and (2) DAO. There is no version with a manual safety. Unlike some of the other P-series Rugers, the P97 is only made in stainless.
The P97 is a single-stack .45 ACP, whereas the P95 is a double-stack 9mm Luger. They have stainless steel slides and barrels, and polymer frames. Both come with fixed 3-dot sights; the rear sight is drift-adjustable for windage.
Mag capacity for the P97 is 8-rounds. It can use the 7-round P90 mags, and the P90 can use the new P97 mags. The factory P97 8-round mags are all stainless. The mags have a removeable plastic bumper/floorplate, and disassembly of the mag for cleaning is effortless. The 8-round P97 mags can be identified by their metal follower (identical to a McCormick Shooting Star); the 7-round P90 mags have a plastic follower. The P97 mags have witness holes, but the lowest witness hole is for the 7th round. In other words, you can't tell if a loaded mag has 7 or 8 rounds installed (unless you're really good at estimating weight) without popping out the top round and seeing if the bottom witness hole clears or not.
The P95 was designed to use a magazine holding 15 rounds of 9mm Luger ammo. Since the 1994 law restricting new magazines to 10 rounds or less, new P95 pistols manufactured after 1994 are sold with two 10-round magazines. The 10-round magazines cannot be modified to take 15 rounds. The pre-ban 15-round mags will still work in the P95, and it is still legal to use them, even in a post-ban pistol. However, they are becoming increasingly scarce, and command a premium price, even for used ones.
The design of the Ruger P97 .45 ACP is almost identical to the P95 9mm Luger pistol, but there are some differences. Function and lockup are identical, but the P97 barrel chamber protrudes a litle higher out the top of the slide when in battery. Field-stripping is identical.
There are some diemnsional diferences between the P97 and the P95. In the P95 (and most Ruger P-series pistols), the frame is a little wider than the slide. With the P97, the frame is the same width as the slide. This is due to the P97 having a little wider slide and a little narrower frame than the P95. The grip on the P97 is not as wide as that on the P95 (because of the single-stack mag), but it is a little larger front-to-back (because of the longer .45 ACP cartridge). The height of the two pistols, from bottom of mag to top of rear sight, is identical. The P97's barrel, at 4.2", is about 4/10" longer than the P95, and the overall length of the P97 is about 1/2-inch longer.
The DA trigger pull of the P97 is long and very smooth, like the P95, but a couple of pounds heavier. The P97's SA trigger pull is heavier than the P95, but is usally crisper. The SA trigger pull the P95 is about 1/2-pound lighter than that on the P97; the SA pull on the P97 I measured was 5.5 lbs. However, the P95 tends to have a little creep, whereas there is usually much less, if any, creep in the P97's SA pull.
The effort required to rack the slide on the P97 is more than on the P95. The P97's effort is about on a par with most 1911 pistols with a 16-lb recoil spring, but less than a 1911 with an 18.5 recoil spring. The hammer spring on the P97 seems to be a little heavier than that on the P95.
There are some design differences between the P97 and the P95. The P95 has a captive recoil spring, whereas the P97's is not. Both pistols have ambidextyrous decocking levers, but the levers on the P97 are not as wide as those on the P95. As a result, when tucked into the waistband or in an IWB holster, the P97 doesn't catch on one's shirt like the P95 tends to do occasionally.
The P95 has ambidextrous magazine releases, and the releases are grooved. The mag is released by pushing either botton forward toward the muzzle. The mag release on the right side of the P95 tends to dig into the second nuckle of the middle finger on the shooting hand of some shooters; these owners often round off the offending sharp point with a file or Dremel tool.
On the other hand, the magazine release on the P97 is *not* ambidextrous. Like the 1911-type pistols, one pushes in on the left-sided P97 mag release button in order to release the magazine. It appears that the mag release could be switched to the other side for a left-handed shooter by just flipping the parts. The P97 magazines have a mag catch slot very similar to that on 1911 mags, but there is a slot on each side of the mag, although only one of them is used.
Speaking of magaziness, the P97 mags are very similar to a 1911 mag, but have a wider and longer floorplate. The front edge of the P97 mag body is not as rounded as a 1911 mag. The P97 mags will fit in a 1911 mag carrier, but it's a tight fit. Wetting the leather a little, and inserting a baggie-wrapped mag overnight would make the mags fit perfectly in a 1911-type leather magazine carrier, but then the carrier might be too loose for a 1911 mag.
With a typical two-slot belt holster, or a vertical scabbard (tunnel-and-slot) leather holster, either the P97 or the P95 conceals easily underneath a flannel plaid "ourdoorsman" shirt or a windbreaker. The P97 is a bit better in this regard than the P95. The P97 Concealability is on a par with a 1911 -- the slide is thicker, but the grip is probably a little narrower on the P97.