This is an accepted solution.
Both of these apps will sync your products with the Google Merchant Center and any product updates are pushed by the app. If your goal is only to sync your products with GMC, then you can choose one app rather than using both. However, Shopify's Google Shopping app allows you to create Smart Shopping Campaigns as well. This is of course essential if you want to list on google shopping. You need to consider what you need from these apps before you make your decision as both offer support for labels, integration with GMC and advanced filtering.
Hope that helps
You have another app that can give you a more comprehensive solution to your Google Shopping ads, AdScale.
It uses AI to automatically advertise and optimize your ads on Google Shopping ads. It also manages your feed and creates you a Merchant Center automatically, there is no hassle in creating your Merchant Center and creating your Shopping ads.