Hi,
740W capable Switch differs from 370W one by the the total power can be delivered by the Switch. meaning at a time , the Switch can deliver up to 740W or 370W maximum.
Now, Choosing the appropriate PoE Switch depends on the power consumption of the end devices. for example, some IP phones requires only 7watts to operate, others with enhances features requires more , Access points also varies.
Your decision to choose the correct Switch depends on the devices that will be connected to the Switch and how much power they would need. check the Data sheet of the devices that will be connected to the switch , calculate the sum of the power required and choose your switch accordingly.
BR,
Mohamed