Expatistan - how expensive is your city ?

An interesting site - thanks to @urbanphotoblog for the tipoff...
It's designed for those who are thinking of moving to another location. It allows you to compare the location of two cities in terms of the cost of living there in a number of categories.
There are almost 1500 cities in the database.

Would be a good activity to explore how the cost of living varies between a number of cities, and also to explore the accuracy of the information on which it is based...

For example, two of my best friends moved to Wellington in New Zealand several years ago, and have a great quality of life...  How does that compare in price with Norwich in the UK.
Is it cheaper or more expensive ?