The Stealth Tank is priced at 1500 credits, armed with two rocket salvos each capable of firing 8 surface-air/surface-surface rockets which can be upgraded with Tiberium Cores to increase damage, is the fastest and most agile armored vehicle ever made and of course is >98% invisible from over 30 meters.
The Planetary Assault is priced at 3000 credits, armed with 10 mini-fighters that each have a high-heat plasma cannon effective versus tanks and air-craft, can be upgraded with a force-shield that can deflect a certain amount of damage before having to power-down and recharge. The PAC can also generate a small ion-storm which not only shoots lighting at foes but also boosts the attack power of the ship. The PAC also has advanced scanners which render even Nod's most advanced stealth tech useless.
So if the two are each the other's natural enemy, which one would likely win?