Welcome to the forum!
The entire 3rd generation line of pistols was never as popular as say.....the Glocks. Why? Well S&W never really promoted the features or did as much advertising as they do these days.
I think Mas Ayoob sold more S&W 3rd gen pistols than S&Ws advertising department ever did. Mas Ayoob wrote about his experiences with them fairly often. He also competed with them and did VERY well.
The 457 is a very fine compact 45. VERY accurate and bet your life reliable. It is a "value line" version of the 4513TSW. So it has some cost cutting features such as less slide finishing, some plastic parts and cheap sights. Most of the plastic parts can be replaced with metal 4513TSw parts, should you wish to do so. The sights are the only thing that ever really bothered me on my 457.
I'm told that Novaks 45 Shop in Parkersburg WV now has sights for the 457, although I've not yet verified that as fact. Besides the sights the only thing I would change is the grips. I prefer the Hogue rubber grips to the factory Xenoy grips. Makes the gun fit my hand better.
When the 457 is found used in the $350 to $425 range I think it is still a value. I wouldn't pay more than $450 for a 457 though as you could get a used 4513TSW for that. The 4513TSW has enough extra bells and whistles such as full length box frame rails, front strap checkering, Novak night sights, ambi decocker ect, that it is much more gun for the money.
Absolutely nothing wrong with a 457 though. I'd buy another 457 long before I'd buy an M&P45 or any of the other "popular" compact 45's.
Hope this helps! Let us know how your new 457 shoots.

Regards 18DAI.