If you're a 150lb neophyte, and you're trying to build mass, I would say shy away from cable/pumping movements, but I also don't think you should avoid them altogether.
Try building an Arnold-like chest with cable crossovers or flyes...tell me how far you get with it. Then compare to doing nothing but bench presses.
There's a place for movements involving cables, DB's, BB's or whatever. If you think doing crossovers with give you huge pecs, I would guess you're incorrect. But if you combine crossovers and bench presses in a superset, I would be apt to agree with you.
And I say it all the time, there is a time and place for nearly every thing you do in the gym. The key, or "secret" as some like to dub it...is finding what order and/or when to place it in your routine.
