Speakers better than the MMGs?

I currently use a pair of MMGs. Love them...but are there anything else out there that beats it and cost around $500-600?

Have been looking around but always ended up doubting that they would sound better than the MMGs....Has anyone own the MMG and then later bought something else that was much better? Price must be around the $500-600 though...that's my budget!

Anyone heard of Tube Audio Designs TAD-805C speakers?

Thanks!!