You could get a 4040PD in 80% condition for less, but it's not a bad price either, considering the fact that you don't see many for sale. I think I paid about $25 less for my first 4040, and it was pretty well used.
It's a good model, and parts, including magazines, stocks, sights, and springs, are still being made and sold by major retailers, and AFAIK, also by S&W themselves. Parts like grips, mainspring, and magazine springs will be the same as the model 3913, and most of the internals are also universal 3rd Gen parts. Brownell's has had NIB 4040 mags in stock for the last year or so (though I haven't checked lately).