On a day like today it was great - 40 degrees and rain,a nd my gym had a 90 min class.
I also go regularly during the week as I get a better workout aerobically, than I would if I just jumped on my trainer at home. Youc an come straight home and jump on trainer for another 1hr, so you get in 2 hours, which is hard to do for me on trainer only.
Once you get used to it, you can customize it and do your own thing without being too obvious. Find a teacher you like and music you like and it is a great cardio wk out.
Bring your HRM and just go do the workout you would have done at home or use it to just stay in a certian HR range and work on some skills.
High speed cadence drills - 120+
Lower speed big gear stuff
Intervals -what ever time you want to do and recovery. I may follow class as to sit or stand but follow own plan on the intervals etc.
Solid HR at steady Z3-4 HR
Easy all day for recovery ride or
warmup to lifting /core wk out after
I figure it is 3 more hours of cardio a week for me and it is not junk miles if you go with a plan. If I do not like th teacher I sit in back and do my own thing.