My experiences
Here's my used gun experiences.
a) First gun, Ruger Mk. II Target. Great gun. Accurate, reliable, and it was not even broken in yet when I bought it. This is my favorite handgun. Highly recommended.
b) Bought a used SKS. They're a lot of fun, but they don't seem to be very accurate. This is pretty much accepted for these and AK-47s. Bought it for $125, sold it to a buddy for $100.
c) Bought a used S&W 64. Something was jacked up with it, the cylinder didn't want to come loose. Re-sold it at a loss. Didn't want to have to pay and wait for it to be fixed. It wasn't very accurate either, no matter what I did. I think it was a police trade-in from CDNN Investments.
d) Bought a used S&W 29. (44 Mag, 8-3/8" barrel) Great gun. But it shot loose with magnum loads. Sold it to break even and bought a Ruger Redhawk.
e) Ruger Redhawk Hunter, 7-1/2" barrel, 44 Mag. Ruger had a manufacturing defect in the 80s in which the barrel metal was damaged from using a bad barrel lube when the barrel was machine-tightened into the frame. On my first shot, the barrel broke off and tumbled downrange. With the scope attached. The scope (Leupold 4x) was undamaged physically, but picked up a scratch. I sent the gun back to Ruger with a letter telling them what happened. They replaced the barrel and sent it back. No charge. This is probably my second favorite handgun. VERY accurate, and easy to shoot with light hand loads. I can shoot 2-3" groups at 25 yds. with it all day long, and I'm sure the gun is capable of better. I think I paid about $450 for this, including the Leupold scope. The guns alone now have an MSRP of around $750. It was a good buy.
f) Marlin 39M. (carbine, straight-stocked version of the famous 39A, lever action 22) The lever was a little loose, but the gun has a lot of character and is very accurate and reliable. I love the break-down option. I think I paid $400 for this.
g) Taurus PT-92. This is a previous generation Beretta 92. It had the frame-mounted safety. Great gun, very accurate, reliable, and comfortable. I paid $300 for it. Sold it for $350 to raise money for a Glock 34. (competition 9mm model) Should not have sold this one; it was a far superior gun to the Glock, IMO. (more comfortable, more accurate) I'd buy another one of these in a New York Second, if I were in the market for a full size 9mm.
h) Bersa 383 (380 Walther PPK/S "homage") - Bought this off a friend for $100. I couldn't talk him out of his Makarov, so I "settled" for this. But this is the superior gun, IMO, even if it doesn't have the cult following of the Mak. The trigger's better, the sights are better, it is a more comfortable grip (kind of like a tiny Beretta 92) and ammo is easier to find locally. Fantastic gun; maybe my best used purchase. This was the predecessor to the "Thunder" 380s they make now. It is pretty much the same, but the mags are different and are a bitch to find now.
My bottom line is not to buy a used revolver sight-unseen, unless it is from a trusted source. Maybe autos are no different, but that has not been my experience. It seems like any hack (like Taurus) can make a decent auto, but revolvers are harder to get right and keep right. There's no such thing as timing issues on an auto, and lock-up is a lot simpler.