When we did do schema markup review, I will say the performance was excellent. We also use a lot of inner pages to rank for "secondary" terms (terms apart from our main keywords) so it was very beneficial.
However, I'm more wary than usual of penalties these days. Even if it's slightly possible you could get a penalty, I avoid it. Shooting yourself in the foot is not fun. And Google penalties are the worst because many times you don't know you've run afoul unless you get a manual penalty (rare) or your rankings tank. Unfortunately, in my experience, algorithmic penalties aren't always so heavy handed. Sometimes a drop of 2-3 spots over a month or so (almost imperceptible if you track rankings daily) could indicate a penalty. And with that being said, there's plenty of room to run afoul of schema markup issues, especially with reviews. They've already handed out two iterations of penalties for review markup that I'm aware of.