It seems like Stern gets picked on a lot. People are getting out the magnifying glasses and complaining about the slightest imperfection. Reason of course is that we expect a lot when paying upwards of $8000. Pealing decals seem to be the biggest issue along with some kinks in the new Spike system. Overall, I think most owners of Sterns bought over the last few years had no issues that couldn't be fixed without a little tweaking.
I bought a ST over 10 months ago. It still looks brand new after hundreds of plays. I've had to adjust a few things and fiddle with some wires. Sure, I have dimples in the playfield, some cracks in plastics, and normal signs of use. The only thing that failed was an led bulb in one of the pop bumpers. I can argue that it feels cheap, art is meh, and point out all the corner cutting parts like pegs instead of rails. Those are obvious things you have to consider when buying any Stern or really any pin in general. I don't think those things have changed much over the years but price has. Like anything, you have to judge whether you think all the "cheapness" is worth the asking price.