War machines in Heroes V.

Even so, the tent is cheaper than other siege engines – 500 gold, compared to 750 and 1500 for the cart and ballista, respectively. So, even the developers have priced the siege engines according to their effectiveness.

That's clear. But let's not argue about which is better or worse; the tent and the cart both have their pros and cons, so both are good. Therefore, we can say that neither the tent nor the cart can be singled out as superior. The tent's drawbacks lie in its limited effectiveness in battle and its relatively weak healing power. The cart isn't always necessary in battle; all factions are designed so that there are always more melee units than ranged units. Moreover, if the battle is too short, the cart won't be useful at all, or if the hero only has melee units, and those units block the ranged units, they will no longer be able to fire until they are exposed. While they are blocked, the cart also becomes useless. ;)