Mccormack DNA-750 vs DNA-500

I have the DNA-500, How good are the DNA-750 mono's? Are they better than DNA-500? Thanks
Talk to Spearit Sound in Massachusetts. Seriously experienced audiophiles and they sell McCormack and know their products very well. i have done business with them for over 10 years and trust them. Speak with Jack Tozzi. Tell him i say hi. good luck.