I like to do a quick cardio to jump start my day; the bosu is a good half hour combination of cardio and things like squats and crunches at the end, so its something to fit in before I to go to class. Its also pretty fun. I don't think I'll be at the gym that much? The Bosu I have at home, the circuit I train on is down on the street, and the machines at the school gym won't take too long. I never really liked the idea of free weights somehow, machines are just easier for me to use, I wouldn't know what to do with free weights at all.
I dunno - I consider any workout longer than an hour to be a long workout. That said, you can do just about anything with free weights that you can do with machines (certain exceptions might be back work), and you'll get a better workout. You'll be using more of your stabilizing muscles to keep the weights from moving around. Compare a chest press on a machine - your arms moving along the track the machine dictates - as opposed to a bench press - your arms moving through your natural movement pattern, using auxiliary muscles to balance the weights left to right and back and forth. How many times in real life does something you lift come on a track? This instability is why some people (like me) enjoy using kettlebells, for extra challenge in that area.
Consider this too - (taking a page from NROL) if the point of your workout is exercise, when you're using machines you're nearly always sitting down... With a little research and questions here I'd think you could come up with an equivalent or superior free weight option.