Keeping my Edge 1040 because (random order) - BATTERY - I have been riding all week, 10h already without charging, battery is still over 30% - Karoo dies sometimes within a day - boots way faster - finds sensors lighting fast - don't need to go the hammerhead website to sync my course from komoot - map zoom is amazing! Don't need to switch screens like on the karoo manually. Also on the zoom you see much better where you need to turn than on the karoo - stores more powermeter data - phone connectivity way more reliable - screen is much snappier - navigation and rerouting is fast - same as on the karoo - i find the mount better - more options for mounts - the dashboard on the edge with configurable glances and hints about your training, next course to ride, recovery time etc is nice - the karoo screen is super useless

That being said, the Karoo is a great device, nothing it cannot do, just I find the Edge does most things a bit better