I look at it like this. No matter what kind of exercise you do its better than nothing. I work in a jail where there are no weights or anything for the inmates to use. But they find shit to lift. For example they double up trash bags filled with water and make weight bags out of them. With this they can curl, do shoulder raises, stiff leg deads, overhead presses, tricep extensions, rows, and a few other things like calves. They combine that with hundreds of pushups, situps, dips(using the stair railing in the upper tier), pullups(off of the steps), and they do a lot of walking(hours on end nonstop for some) up and down the steps as well as lap walking around the Pod. Some of these guys are bigger, more muscular, and even leaner than a lot of people I see in the gym that hit the weights hard and eat correctly. I know a lot of this has to do with genetics and the amount of rest they get but still these are not ideal conditions to get big under. Having said all of that I still feel that free weights are superior to any machine etc out there. There is nothing like free weights(dead weight in general). But I do realize that you can get big with machines and other equipment that is out there. If you want my opinion on things I must say that dumbells are superior to all weights in general, even barbells. But thats just me.