Hey guys, especially those professional wedding/portrait and event photographers, what flash systems do you use when you're on the go? No umbrellas and stands and fill lights with wireless sync and all.

I have a Canon 580MkII and it does great most of the time with the ample room to swivel and bounce off ceilings and walls but recently I saw the Metz 58 AF-1 with a secondary fill light in front of the main flash head. I also chanced upon SCA flashes.

Anyone care to shed some light on the pros and cons of these flashes and what equipment is best for professional wedding/portrait/event shots on the go? basically not too much fill but ambient as well, yet with enough fill.

Thanks in advance!