Picked up a Speedlite 600EX-RT for Christmas and have been using it with the older one as a secondary flash. It’s been working pretty well so far. I notice that there are sometimes exposure issues that I have to deal with by taking a few photos and sometimes the optical transmission mode is a little bit flaky for the dual flash, but still overall a very nice setup. I am particularly liking doing 75 degree bump flashes with the white card extended when shooting close ups with the 17-40mm lens.
Also got Magic Lantern Alpha 3 loaded up and running. No record continuation yet, but the clean HDMI output is nice and the focus indicators make it FAR more usable as a video camera. Looking forward to getting a chance to give it a try at Excel next weekend. The one minor issue I’ve noticed with the clean output is that when you go to adjust the ISO, it still displays the overlay on screen instead of being able to just work off the LCD panel. Shutter and aperture work fine though without anything on screen. Still looking forward to getting a lens in the 30 – 70ish range, but haven’t decided when or which one to get yet. I’ve definitely been feeling the pain of missing anything in-between 40 and 70mm.