Could anyone please comment on the synergy of these two amps with the HD650? Which one is best, or should I be looking at a completely different amp (max price is $300). Furthermore, how well do they work with HE400s? 

Hello folks.   I've finally saved enough money to buy some new headphones. Unfortunately, I can't seem to decide between the HE400 and HD650. I primarily listen to electronic dance music, also stocking up on film score and particularly good video game soundtracks. I'd also like to game with...