I absolutely love the Mastermind Genius. It is cleaner than the Mastermind with its hybrid cover, and has a strong arcing type of motion. I have used the Mastermind Genius on house and sport conditions with success, and haven't found a condition that it didn't have a consistent performance. Also, It takes well to cover changes.
Comparing the Maxxed-Out with the Meanstreak Beatdown, the Maxxed-out starts up a little earlier. The Maxxed-Out has a strong midlane roll, and the Beatdown has a strong downlane roll. With both having a solid coverstock, they take well to surface changes. I keep both of mine at 2000, and use them for heavier oil.