There is no one hard fast answer to this question.
For many homeowners a lease could be the best way to take advantage of clean solar power. For others who are looking to be in their home a prolonged period of time, or looking for a return on an investment, purchasing their solar system could be the best option.
To make an informed decision, your best bet is to start with a free in home evaluation. Invite a trained professional into your home to evaluate your energy usage and your individual desires and pain points.
With that information, options can be laid out explaining both a purchase and a lease. Armed with this information, you should be able to make the best decision for your individual needs.