Whitelabel or Build your own? Pros & Cons

Imagine a scenario. You and your team have been building a platform for a few months and see a long way to go before it's launch-ready. You come across a company offering almost exactly what you were trying to build, bringing over 5 years of development and improvements to their project, and are willing to let you white label it as your own. Now when you compare directly, you find yourself leaning towards white-labeling as a better solution to offer your clients, which also cuts down your development and go-to-market time. What would you do?