For shooting outside, I mounted one FLEX TT5 on camera to use as the controller, mounted a 430EX II on a FLEX TT5 on a light stand, and mounted a 550EX on a FLEX TT5 on another light stand. This two light setup is very portable and versatile. For outside photography when you have good light, the Control TL system makes it possible to achieve almost effortless high speed sync flash, permitting one to shoot with the lens wide open to achieve a shallow depth of field and catch some good bokeh in the background. Here the camera is in Aperture Priority mode and note the shutter speeds of well over 1/200 seconds, which is the maximum sync speed for the Canon 5D MKII.
NOTE: When using high sync flash with the FLEX TT5 system, I read that channel C2 is better than C1 so that is what I used. I had no misfires with this setup. I tested distances of 100 feet with no problems! Also note that using exposure compensation works to darken the background, just like when not using flash. Sweet!