"Before buy another" what? A replacement drive? Pioneers are often given high marks for the full-height drives but, as your experience tells, "everything can be a crap-shoot".
If you get a replacement drive and can do it locally, then it's easier to return it if your quick tests aren't perfect (burn sample disks on everything - CD audio, DVD video and BluRay data, for example; and then immediately use another computer or other players to test the disks out).
If those aren't perfect, try again. The likelihood of running into more bad units is always there for each vendor and model - but the chance of finding well-performing models is even greater. Take a deep breath, dive in, and plan on spending a few hours testing. And then realize that most hardware will fail in their first few uses, so keep your receipt for trade-in purposes.