Well yeah 8kg is deffo heavier than 7,5kg comp bike lol, still something I would classify as superlight. Gilles for example uses carbon forks on his training bike too...Back to the smith vs free weights question, It is harder for someone who doesn´t use this machine very often to use the same amount of weight he uses with freeweights, no two ways about it. As isitafox said, bar moves in straight line and that isn´t optimal for pretty much every exercise, maybe behing the neck shoulder presses. If you always use it, of course you will accustom to it.