Obviously it's a trade-off and when to rack is going to be an opinion based on experience or consensus. There is no hard and fast rule for racking to secondary, it's more of a continuum. Racking before FG is reached will ensure that it sits on the yeast long enough to properly ferment and the yeast can clean up after itself, however it will not be producing CO2 as much so after transfer, the headspace will be O2 and there is a larger potential for oxidation. Racking slightly before FG ensures that CO2 is still being produced and will displace the O2 in the headspace after transfer but runs the risk of less than optimal attenuation from pulling it off the majority of the yeast too soon. Whenever you decide to transfer, if you even do, comes down to how you view these factors as important to you and what you are trying to achieve.
That said, I think a majority of us tend to leave it in primary until it is at FG, no need to hurry it.