I used a Garmin Edge 500 for over 10 years. Buttons were fine to do the few things you could do on it. I got an Edge 530 last year. Buttons require too much effort and taking your eyes off the road too much to get to many of the newer things I'd like to do with it occasionally while riding. I might get used to it. But I'll recommend a touch screen.
I don't know about the Edge 830, but my son had occasional issues with sweat getting on his Edge 820's touch screen and it not responding. I think Garmin got most of the issue fixed in several software updates. But he says the touch screen on his new Edge 1030 plus is so much better. And the 1030 seems to have better processing power so you don't get as many delays with things like scrolling around on the map or sending the ride to Garmin.