Freeweights alone are okay. Freeweights as a backbone with some machine use mixed in is okay too. But machine use alone potentially paves the way for joint issues and unecessary injuries. The planes of movement forced by some machines can have directly degradative effects on the joints of certain individuals depending on body proportions. Also, there are small muscle and joint tissues which come into play in the stabilizing of freeweights. Many machines develop the larger muscles while insufficiently training these smaller stabilizers to prepare for the increased abilities of the larger prime movers. That means when you go out into the real world and try to apply your strength in either basic physical labor or your favorite athletic endeavor, machine-trained exclusively gives the potential to either perform far below expectations because the nervous system has limited the firing of your larger muscles due to perceived weakness of the smaller stabilizers or the larger muscles are able to maximally fire and end up effectively overpowering the smaller stabilizers causing injury.
The most well-developed competitive bodybuilders have used freeweights as their mainstay.
For me, I don't really care much for machines other than the Reverse Hyperextension, Cable Rowing variations, Donkey and Seated Calf Raises, Leg Curls, and occasionally Leg Presses and Leg Extensions.
