457 Thumbs UP
When I was considering getting one of these, I looked at them long and hard and didn't find any problems with them. I read lots of comments (including from ISP above) who trusted their lives to them everyday.
I found one in great shape and I love it. (full disclosure: I am a huge fan of S&W Third Gens & the 457 was one of my first)
It is accurate, easy to shoot, easy to take down, and fairly common for accessories.
Side note: I recently found a used H&K .45 that caught my eye. I took my 457 out and compared it and found it very similar. The H&K was a great weapon...but I figured for the $900 I could send the Smith off to the performance center, add different sights, have the barrel & slide coated in a couple different finishes and still come out about even.
If you find a good one, it will serve you well.