Sterns should have less problems overall versus JJP games as there's less on them but that isn't always the case.
Any new early production pinball machine from Stern and JJP is at risk of having more issues compared to later production games. There's almost always small hardware fixes and tweaks that owners of early production games will have to go through. For less issues overall I would recommend waiting at least 6 months after initial production before ordering any new pin. By the time I did get a new Dialed In LE it had all of the hardware fixes and tweaks from earlier production games made at the factory.