^^ I agree with both of you... mATX limits us when we want to go for tri-gpu setup or if we are audiophiles who need to put in good sound card into the rig. But then again.. audiophiles would want to go for a good DAC to use with high quality headphones instead of speakers, which would be connected to our rigs through USB ports. Onboard sound chips have improved leaps and bounds now.
@OP - One word of caution though.... If you put in 2 GFX cards for SLi/CorssFire thing... the card which runs in the first slot may report higher temps since there wouldn't be much space between the two cards. This is a common issue with all mATX boards. But shouldn't bother you much since I see that you already have a 7970 from sapphire, so you wouldn't be going in for a crossfire setup in immediate future, I guess

and also the new crop of cards from both nVidia and AMD run much cooler than the previous two generations actually.
And BTW..see this link - "That’s 7074.7MHz On The Maximus V GENE"