divie

Ive recently started using a machine bench press at the gym as i can put more weight and effort into it as i aint got a spotter so i dont have to worry about a barbell falling on me so in that respect its all good.
But how does a machine compare to dumbells and barbell? as im obviously not using any stabilising muscles but i think thats a good thing as its just my pecs that get worked and only my pecs.Im using machines for all my body apart from bicep curls, lateral raises, squats.Any opinions
ps on the machine shoulder press theres handles front and a little back i expect the one further back is like doing a behind neck press and the handles in front is like douing a military press am i right?(if you understand my crap explanation).
thanks
ps theres no free weights at my shit gym