Bought one last week and both my wife are very happy with it - makes a good cappuccino and is simple to use.
From what I could tell WS has an exclusive on the glass, but they sell a polished aluminum one that is more widely available. http://www.bialetti.it/uk/catalogue/scheda.asp?id_cat=69
Also over 200 reviews of the aluminum one on Amazon:
As an fyi - we use it on a gas range top.
What drove my decision to purchase it:
Quality (both product and the end drink) - have had espresso made with bialetti before and was as good as "machines" costing hundreds more
Size - small and doesn't take up any counter space
Ease of use - couldn't be easier to make a frothy cappuccino