Short Answer… both
While both products are hugely popular and growing at an massive rate, especially due to Covid-19 Isolation protocols.
Teams is ideal for internal meetings and communication. You can externally share meetings to small groups too. This is my preference for most of my online meetings as I know the content is secure and restricted only to those that I provide access to. The benefit of creating documents and adding tabs and apps to the workspace far outweighs the limitations of Teams. External users aren’t required to download an application, they can attend and participate in a meeting in the browser.
With that in mind, there are limitations in Teams. Therefore sometimes we choose to run meetings online via Zoom. The number one reason for this is that Teams is currently limited to only 4 video feeds being displayed – those are the 4 people recently speaking. During these difficult times, I like to see as many people as I can, whether they are talking or not – usually it is the quiet ones who need the most support. Therefore Zoom offering up to 49 video feeds has become my go to tool for larger video meetings.
I expect Teams will catch up and therefore I may consider shutting down Zoom, but for now the benefit is justified.
Integrate Zoom into Teams
There is a great article here on how to integrate Zoom into Teams for a more streamlines and efficient meeting process.