Although I don't own one, the general consensus on the S&W PPK's seems to be that they had some teething problems early in production, and there was a recall, but the recent ones are very, very good. I've examined several, and asides from having no apparent flaws in workmanship, the DA trigger pulls seemed smoother and lighter than the Interarms / Mid-South Ind. and Manurhin guns I've examined.
Speaking of Interarms and Manurhin, although most of their guns look great, remember that you're NOT going to get factory service for one!