I am not fitness expert, but I have to tell you that I have been at Bally for over a year now, and I agree with you. I was always told though, that fluctuating your heart (by doing "random" on the machines) actually gives you more of a work out because your body has a tendency to get used to the rate at which you're working.
If you're weight lifting, you want to rest between sets for at least 45-60. If you're doing cardio, I would keep your heart rate up for the entire duration of your workout (minus your warm up and cool down).
I can tell you for me, the cool down is VERY important. I work out pretty intensely, and if I would just get off, I would be light headed, dizzy, and discombobulated for about a half hour. Allow yourself the extra 2 or 3 minutes to get your body temperature back down to a normal rate.
Good luck at Bally's! I absolutely LOVE my Bally!
Monday is my official weigh-in day. I'm putting my goal at 130 and I'll go from there.