The best way to test a product like this is to use it, make sure it provides a stable powersource for your devices and check there’s no obvious design flaws that crop up when using it etc so that’s what I’ll be doing.
After using it for a little while it didn’t cause me any problems, even when powering a device with it’s USB port and charging a netbook at the same time. After some probing around with a multimeter I couldn’t see any issues with it providing stable power for your bits and pieces.
The connections are all solid and very unlikely to fall out or be accidentally pulled out. Compared to similar products the size of the transformer surprised me. Certainly lives up to the mCube Mini name.