I wonder how many registered (i.e. paying) IDEA users there are.
I am actually a freelance software consultant, and I tend to advice my customers to use IDEA, as I think it is a brilliant product.
However, they almost always ask me this:
1) Why pay whereas Eclipse is for free (I would be grateful for any link related to first point) ?
2) Given growing Eclipse popularity, how to be sure that IntelliJ will still be there in two years ?
To answer latter one, knowing the user base size would help.