Personally, I mostly buy used guns because it is actually easy to find pretty much what I am looking for, at a better price, and - at least for the present - little or no paperwork involved. Have never had a problem with any of my used Rugers, but did have a new one that had to be replaced.
The comment about the AMT Hardball caught my eye. I have never owned or even handled one of these, but am considering one for my next 1911 purchase. They seem to have some features I like - and when I see one for sale they are not really "cheap", so they seem to hold some value.
My own experience with AMT guns is from a sample of one. Several months ago I was wrecking out an old RV and found an old AMT .380 Backup under the kitchen oven, where it had apparently been for at least the 12 years I have owned the camper. The little pistol also had a fully loaded magazine. Internet inquiries quickly drew a lot of negative comments about AMT, but I cleaned this one up (no rust, just dirt), replaced the trigger spring, bought a couple of new magazines, and found a set of factory checkered walnut grips still new in their box. It shoots and functions fine, for what it is. The only "jams" I've seen were on the last round in the original magazine - which, remember, had lain there loaded for at least 12 years! It cycles and fires both FMJ and most HP ammo, with the only real feeding problem being with some Hornady branded ammo (although other brands loaded with XTP's cycle fine).
The pistol basically has no sights, but is still pretty accurate at the ranges I would expect to use it - 7 to 15 yards. Recently I was made aware that a LaserMax sight meant for the Colt Mustang .380 fits the AMT nearly perfectly, and makes it much more accurate.
In my case, the "price" was certainly a factor - never "found" a gun before! Price aside, I like the all stainless construction, and much prefer the manual and grip safeties to a polymer, striker fired pistol with basically no safety at all. I also like the magazine disconnect. Since literally "finding" this pistol it has been amazing how many gun owners have told me they had one just like it in the past they wish they'd kept. No one who actually owned an AMT Backup .380 that I have personally talked to had any complaints. Not long ago I found another one - brand new in the original box - that I picked up for one of my brothers who had examined mine and liked it - a lot.
From what I see on the used market, occasionally one will sell for cheap - $250 or so - but mostly they seem to have at least asking prices equal to or above those for Ruger, Berreta, and some other small .380's.
The only other .380 I have ever owned was a Belgian made Browning. That one was a very fine gun, but 25 years ago I was not impressed with the performance of .380 ammo. Newer advances in ammo available seems to have made a big difference in the feasibility of the .380 as a defense weapon - although I would still consider a .380 "Backup" to be just that!
Incidentally, of the ammo that was in the gun when I found it , all five rounds fired. The only other .380 ammo I had to try in it that day was from a box I bought 25 years ago - when I had the Browning - and had squirreled away in the safe. That box was Remington FMJ, and all of those fed and fired as well.
For me, this little gun is special, as it has a unique history - and so far both price and performance have been about as good as it gets!