I got the XiaoMi Yi last week.
Mine is not out of focus. It shoots video that is on par or maybe better than my GoPro Hero 2 and better than my Mobius.
However, the XiaoMi Yi does not connect to a computer. To get the video out of it, I have to remove the micro SD card (sold separately) and plug the card into my card reader on my PC. USB is for charging, NOTHING ELSE.
I have been trying for a week to connect this thing to my Galaxy tab 4. No luck. The device will NOT connect via WiFi although the Galaxy Tab 4 can see it and the app for the XiaoMi Yi can see it. This problem appears to be common. There is no fix that I have found and customer service is non-existent. I try for an hour or so until the battery dies out and I have to recharge to try again. WIFI chain smokes the battery on the XiaoMi Yi.
There is new firmware to fix some of the image quality issues and to add stabilization. But, to install it you MUST be able to connect this thing via WiFi to Android. There are no other options to connect this thing, so if you don't have a smart phone, forget it.
Let me make this clear.
The XiaoMi Yi makes no provision to connect to a computer. None. The only way to control this thing and update firmware or settings is through an Android app via Wifi.
YOU MUST HAVE A SMART PHONE OR TABLET WITH WIFI TO CONNECT TO THIS CAMERA.
Your PC will NOT connect to this camera via USB. No attempt has been made to allow this camera to connect to a computer through USB. USB is for charging ONLY.
The default for this camera is to shoot stills, not video. If you want to change that default, you can, but you have to connect to it through the Android app via WiFi to do it.
IMO the XiaoMi Yi is beautiful and has a TON of potential but due to the lack of support, all the instructions are in Chinese and the persistent and common and unresolved connection problems people are having, I wouldn't recommend it yet.