I upgraded to the 530 because I appreciated it's functionality over my older 520. Lots of training dynamics data, maps galore should you want to consult them, and an easy-to-read screen. I prefer a smaller display than the 1030 range, more compact in cockpit and lighter. Good visual interface with Garmin Varia radar. Only drawback is that the battery may require more frequent recharging, depending how many features you activate.
The Edge 530 has been a great addition to my cycling. With the integration w Garmin Connect, its very easy to create training workouts, custom routes, and also more detailed performance stats from each of my rides. I've used it for both road, gravel, and mountain biking and its well suited for each discipline. The battery life is solid. I've only done 1 longer (5 hours) ride with it, but had no concerns of it dying somewhere along the way. Normally, I use it for several 60-90 minute rides a week and typically only charge it once every other week. It integrates seamlessly with all of my sensors (garmin speed and cadence), heart rate strap (garmin chest strap), and lights (garmin varia headlight, garmin varia radar). It has changed my cycling experience. The only reason I didn't give it 5 stars is that periodically there are some small annoyances like auto downloads restarting your ride, but these are few and far between.
Great dual mount however it starts rattling on the first 20 miles of the second 50 miles ride. Turned out, the front piece unscrewed itself from the main body. Its a nuisance to tighten the screw every after ride but I kept it due to its purpose to clean up the cockpit. Well worth the money I spent.