That impression was/is wrong. I've had about 20 15-2's and 715's, and only one came with any issues, and it was fixed in a couple of minutes. I rarely had to resight my guns, and I changed barrels a lot. They stayed close enough for security/combat work without any fuss. The trigger return problem was probably just the gun was full of crud, or the spring had simply died, or someone didn't put it in right. Whatever the cause was, it was a quickly fixed minor issue. I've put thousands of rounds through them with little drama or issues. They are very easy to work on, unlike a S&W gun, and if you look at the mechanism, they make a lot more sense in general.
I presently have a 715 6" and a 15-2 4", both shoot great, and both are 100% reliable.