Android's built-in video player is fine, but it doesn't support all of the formats you probably use. QQ Player supports more formats and has a few standout features, as well, but the video and audio quality aren't stellar and the app's menus can be tough to navigate, too.
The app's language is a mix of Chinese characters and broken English, which makes it difficult to understand at times. It gives you an annoying message every time you try to exit, too. When you first use the app, it can take a while for it to find all of your videos. It searches all of your folders without much input, though. During testing, QQ Player worked well with dozens of different videos from both stored memory and streaming. Video quality was a little hazy, though. You can't change the orientation of most videos from landscape to portrait mode. However, you can snap screenshots and change the player's resolution mid-video without much trouble. A standout feature is the ability to make a video password-protected. This sends it away to a private list that only you know how to access. That means this app eliminates the need for other hiding apps if you have videos you don't want everyone to see.
It's not likely that this app will replace some of the other top video-playing apps in the Play Store. If you already have one you like, this app doesn't offer too much to convince you to switch. Give QQ Player a shot if you're still looking, though.