Really I don t see how the two board philosophies are comparable...
Whoever needs 32bit mcu power and is using arduino would have better results with something like the tower or the propeller.
On the other hand, if you need only simple things, arduino is hard to beat for its price, size, features and ease of use.
Using a 32bit platform for let s say a simple temperature logger, would be like killing a mosquito with a patriot missile... Just plain expensive and pointless...