I always prefer outdoors, and I really only stay indoors when it’s raining steadily or freezing (or both).
I did a 2.7 endurance today (Homers Nose) and by HR it was almost the same as another 2.7 earlier in the week, but I was just so much more aware of the work. I rated it Easy, but that was so that I didn’t point my prediction in the wrong direction. Can you switch back and forth and not throw the system off, assuming you’re like me where you just put out more power outdoors?