Hot water tanks and tankless hot water heaters each have their advantages and disadvantages. The type you decide to invest in will depend on numerous factors. Two of the bigger factors that you will need to consider are cost and space.
Hot water tanks generally cost less to purchase and install, however they take up much more room. Tankless hot water heaters on the other hand, generally cost more to purchase and install, but do not require much space as they are wall mounted.
If you are not sure which type of hot water heating system is right for your home or business, contact a local plumber. They will be able to help you determine the right hot water heater for your situation.