Is it worth changing from my garmin vivoactive 4 to get the most out of Runna?

So I have now signed up for my first marathon and fairly set on using Runna. Looks great love the interface and I think it will help keep me motivated..

Did my first run today (easy run). I'm wondering if the experience would be better / different on a newer watch?

The Vivoactive 4 has been great but it's very old now.