Machines vs free weights
"the truth is usually in the middle." Charles Staley
"it's like firing a canon from a canoe." The Evil Russian - Pavel Tsatsouline
"Iron weights are the bread and butter of any aspiring hardcore lifter. You may be able to lift 75lbs on a machine, but when you try that very same exercise with free weights you would be hard pressed to lift the same weight." Ron Harris

I like free moving exercises because they are more effective for the development of strength and balance in an unstable environment. This is even greater when swiss balls are added to your training.

You decide for yourself what you want to use. For me, it will not be machines, except for maybe an occasional use of the leg press machine.