The best is to take care what you install and where you install from. If you stick to the Play Store (and especially if you check permissions are reasonable before installing) you don't need an "antivirus". I've put that in quotes because there are no true viruses for Android: the biggest threat is trojans, i.e. apps that have malware hidden in them, but these require you to install them.
If you live dangerously with your app install habits, or just feel you need one, then stick to companies who have a reputation to lose, and for sure avoid CM Security (or anything else from Cheetah Mobile - that company makes its money by mining your data, so their apps are frankly part of the problem rather than the cure).