The great thing about that bag is it's silent! No zippers or velcro (well there is but it can be silenced), for me it's ideal.
Changing lenses becomes as easy as changing gear, I don't even notice it now. You can also anticipate the lens you'll need most of the time. I shoot weddings, so the risk of missing moments isn't any greater. But having the right bag is key, without the LC3 my photography life would be much harder. I have tried a shootsac before but it grips the lenses.
I put small cotton flannels in the bottom of the 3 LC3 compartments, I can then just drop stuff into them without thinking. The rear compartment is big enough for batteries, a flash gun, flash trigger of some sort etc... Also has a slot of business cards which is really really useful to be honest.
I have a larger shoulder bag that I transport things in, it stays in the car now with the spare bodies etc... and the LC3 sits on top of everything.
Cheers
Cris