+1 to this. I also have several apps in the Google Play Store. Unfortunately, the knock-off apps are all around our apps, sometimes ranking higher in popular keywords. Some even post a screenshot of our apps!

Heck, some apps are so bad that they ruin the reputation of the entire niche (for example, a document scanner app). If the first few apps that a user downloads does not scan documents, he's naturally assuming that no apps can do it.

Reporting those apps never worked, so I stopped reporting them. Instead, we now focus on improving our apps and hoping for the best.