The course following works fine, but it’s not brilliant. You get a wiggly line on a small screen to follow. Find it ok for road rides, but trying to follow a route around swinley the other day was quite tricky. Oh and it did lock up and freeze the screen on one road ride, I was about 10 miles of course before I realised!
Does indeed work well on a turbo trainer, can show power too if you have a suitable power meter. Use it a lot for that. Also the garmin connect stuff is pretty good (though I’m told there’s better out there.)
Being able to program intervals is good too, though tend to use that more on the 405 when running.