I run the 1030 on my Road and Gravel bikes. Main reason is I often use GPS routing and its nice having the larger screen size for this feature.
For my mountain bike, I use the smaller 830.
Both work really well but I still have chronic issues with both consistently connecting to my Pixel 4 XL phone. This has always been an issue with Garmin head units for me with a variety of Android phones over the years. At times it will connect and other times it won’t and I have to go back a re-pair them.
I don’t notice a big speed difference between the two.