Should I get 2 of these or 1 with a lower grade secondary monitor?

When not gaming, it is nice to have the second monitor as an exact duplicate of the primary.
When you drag pages from one to the other, they will retain their size and color.

OTOH, a different secondary monitor will still display whatever you put on it.
 

I have a system capable of powering 2 of them but it is a question of whether it is really worth spending the extra cash on an 120Hz secondary monitor when i will only be gaming on 1...
 


If only gaming on 1 just get a 60Hz for the second one - you could even still game on that :O