I have a Hammerhead Karoo (1st gen) which doesn't need an app at all, you can feed it via the Hammerhad website, it connects via WiFi and downloads everything you might have planned online. In ride you can just zoom the map, tap wherever you want to ride and it calculates a route, even when you're offline, you have to download maps for your region beforehand though. You can't get a Karoo 1 new, but on ebay you can get them for way less than 200 Euros. The successor Karoo 2 costs 400 Euros, IMHO it's not worth that price. Hammerhead releases software updates every two weeks (seriously, look at the
change logs). The only issue is that the Karoo 1 doesn't have a speaker so you have to look at the head unit quite often to not miss a turn while Wahoo and Garmin units beep when a turn comes up. You can connect a bluetooth headset/speaker, then you have voice prompts via those. You can connect loads of sensors via Bluetooth or Ant+ as well, even a Garmin rear radar connects without a hitch and the head unit shows when someone (or even multiple someones) approach from behind. You can link Komoot, Strava, Ride with GPS, TrainingPeaks and Xert accounts as well.
The Rose Pro SL Disc looks good, no objections from me.
