Are cheap Chinese peltier modules efficient?
The cheap Chinese peltier modules are more or less exactly the same as the expensive ones. The Chinese ones are cheaper because they get cheap postage, and often come from a nearby factory. 

Next, peltier modules are VERY inefficient. At the best of times they use around half of their supplied wattage, and can be expensive to run. This disadvantage however is offset by just how cheap they are (Around ~1£ on eBay). 

To decide what version of the TEC1-127XX series, you can look at the last 2 digits to determine how much it consumes and moves. For example, the TEC1-12706 moves 60W, the TEC1-12707 moves 70, the TEC1-12715 is around 150W and TEC1-12730 is about 250W.

TL;DR

There's little difference. Just buy the cheapest.