Machines were actually built to advcocate proper form and
safety.But without knowing it, machines are very bad for your
joints as they force a very stiff movement as compared to
freeweight.
I can safely tell you that many people's rotator cuff is f*cked up
after benching on the smith machine.
Besides machines do not even train the stabilizing muscles at
all.
The only machines that are okay in my opinion are cable pulley
machines.They allow a more free movement and are more
flexible.
Think of this situation:Would you rather shift furniture that can
only move straight(like most machines) or shift furniture that can
be moved in any way(free weight).
Forget about all the hyper mumbo jumbo rubbish new age gizmo
machines.Its back to the basics...
any place with more machines then freeweight is called a fitness
centre not a gym.