Good question. We do plan to include the option to brand your correspondences with Adobe Send, and you can expect to see that feature added to the service later this summer. In the meantime, if branded emails are an important part of your workflow, we recommend sticking with SendNow until we update Adobe Send in the next couple of months. Don't worry, we won't pull any rugs out from under you - we understand that custom branding is important to many customers, and there won't be even a single day when it isn't available in one or both services.
Let us know if you have any other questions!