[PD] max msp vs pd

[Matthew Williams]

Ok i'm curious .... why would someone spend 400 dollars on max when you 
can get pd for free.  Is it because of the ability to make plugin's 
using pluggo.  But can't you make plug-ins from pd as well.   I was 
going to buy max but i came across pd and thought,  "this is great..max 
for free."  Am i wrong.  And yes i read about the differences .. but 
they don't justify 400 dollars.

wondering,  matt