I've got a 638 and a 438.
And at $400 I probably would have picked that one up too.
I've got hundreds of rounds through mine and no mechanical issues thus far.
The 438 did have to be sent back initially because the barrel was screwed in a degree or two past zero, resulting in a cockeyed sight picture.
But S&W remedied it quickly and it's been good ever since.
The only thing you may or may not want to do is pull the ILS and replace with a plug, although my understanding is that the unintentional locking really only happens with the Air-Lite 357's.
The guts are largely MIM these days, but so is pretty much everything else out there and they seem to have it well handled.
The finish on the aluminum will wear relatively easy but in no way does it impact reliability.