Steelseries Siberia V2 or Monoprice 8323

So I impulsed bought the Monoprice 8323 headphones after seeing the build a better headset video. 

The thing is I own the Siberia V2 since it was a gift last year and have been using that as my primary set of headphones. 

Generally speaking, would I hear the difference easily if I use the monoprice ones or is it all subjective? 

Would I need an amp for the monoprice ones as well?