Max is a direct-combat specialist, possesing significant firepower bonuses to ground, air, and naval direct-attack units. The added firepower is usually enough to overwhelm most other CO's directs and put armies on the defensive, especially on maps spacious enough for direct units to roam free.
This advantage is offset by range and firepower penalties for his indirects, usually putting Max into situations where he must gain a decisive advantage before the opposing army fully develops and pushes him back with superior indirects.
Day to Day: All direct non-infantry units have +20% attack power. Indirect units are 10% weaker, and have -1 Range.
Power: Max Force -- Direct units gain +1 Movement and their power increases by 10%
Super: Max Blast -- Direct Units gain +2 Movement and their power increases by 30%
Max favors a highly offensive playstyle; try to secure an early advantage with your tanks, preferably before the enemy can set up a defense. Do so by trying to trade using his boosted tanks.
Air units, if available, can help secure such an advantage; almost all of them benefit from Max's powers and are hard to counter with other air units.
Max's powers are handy for pushing your direct-combat advantage and busting through chokepoints and meatshields alike. If, however, the opponent falls back, expecting a power, advancing a little forward and biding some time will help gain ground.
Indirect combat is difficult to utilize effectively when playing as Max, but some rockets or artillery might find some use, especially in a standoff, or in fog.
How to Counter Edit
Against Max, playing more defensively will help a lot. Focus on developing a good army, improving economy, and taking good positions, deterring attempts by Max to harrass or trade all the while. Staying on better terrain will also help deter attacks.
Once a decent force (backed up by indirects) has been organized, one can then try to push Max back; this often results into a loss for him.
Take note that Max's direct units will still lose vs a first strike by the equivalent unit on similar terrain; however the attacker will still receive significant counterattack damage unless commanded by a CO with better day-to-day abilities.