Well it's initial cooling ability is pretty weak. It will keep a pre-chilled can of soda cool for a while but has a hard time cooling down a warm can. It will, but after over a day. With a few simple modifications, I was able to double it's capability for almost nothing.
Trick one was to add a larger and more powerful fan to the heat sink. The cooling element(and yes it is actually a cooling element, not just a heatsink) works on the property of dissipation, so adding a fan means it directly cools better. Trick number two, and the biggest help, was insulating it properly. Any refrigerator needs insulation to cool worth a crap, and this unit is just thin plastic. I added some thin bubble wrap/foil ducting insulation inside the box and a piece of foam covered in the same insulation in the hollow door. After these two very simple mods, the cooling got miles better and it actually manages to chill a room temp can pretty well. This thing is a great basis for a fun project, but isn't a great product on its own. They could have put more effort into it.