It depends on the duration and purpose of the trip. The ESTA is a tourist and business visa and only intended for a stay of 90 days per visit, other visas are also for working or studying purposes and support a longer stay.
Citizens of Visa Waiver countries can also apply for a regular tourist visa which also has a longer validity. This can be a good thing if you are travelling to the US frequently and if you do not want to issue a new ESTA every two years. There are certain things that you are not allowed to do inside the US while travelling under ESTA (e.g. getting employed). As soon as your intentions are others than travelling for tourism or business purposes, ESTA is not the right travel permit and you should check other visa categories.
In general, ESTA and B1/B2 (regular tourism and business visa) can both be used by citizens of VWP countries however, in most cases ESTA makes a lot more sense since its processing fees are smaller and its processing time is way faster. You also do not have to attend to a personal interview when applying for ESTA while this is mandatory when applying for B1/B2.