I have both and the transition only takes 15 mins even with a heated screen as I have made the connections easy to separate .
As far as road vs track I use the full screen for the road and the aero for the track , it's great fun on a nice summers day going for a blat with an aero screen ,but have now decided it's too risky without a full face helmet and with that on the fun has gone anyway !
Perhaps I am just getting old ,but I would never take my grandchildren for a ride without a full screen so why risk it yourself.
Cheers
Rhys