On paper it should lose to the Tiger more than half the time.. But in practice, it's a better place to be than in a Tiger.
The tiger has a slow turret which matters not just against the M4 but also in dispatching faster light GVs, crappy HE ballistics (to damage light GVs), has no smoke ability, and all these handicaps are multiplied by the higher perk cost, which means there'll be multiple M4s for every Tiger, despite the M4 being superior in most circumstances the two meet in, in the game.