Had both at one point in time and Deluge stayed. One is analogue the other isn’t. Beyond that I would think sound engine wise, A4 has a more direct and impactful punch. The tweakability and macro effects are so good but requires pre planning and configuration. Deluge ain’t a slouch either. With community firmware update Deluge now offers clip launching and live remixing in a very performance friendly way. Prior to this I would say the Elektron workflow is fastest to deploy and perform. Now it’s pretty even and more a matter of style and choice by users.