I heard that you should stay away from the all-in-one units like the 4 channel that you have there. So I bought the 16 channel version (similar to what you have there, if not exactly the same - got it from user photogearok) and it came yesterday so I have had a chance to check it out. Basically, it would fire that rarely on the hotshoe on my 10D, I have to run it using the pc sync cable, and i just half mount it on the hotshoe so i don't have to hold on to it (but the hotshoe doesn't actually fire it, so it acts more like a cold shoe). Good unit though, not sure why it wouldn't fire from my 10D hotshoe.
As far as misfiring or not triggering, well, I can't talk about misfiring coz it never misfired for me as I was indoors in my house, but it triggered 100% of the time (once I figured out that it wasn't triggering properly from my hotshoe), doesn't miss a beat, so long as your flashes are running on good batteries and charging up quickly.
In terms of running it with a sunpak, I bought a cable from flash zebra, which connects the 6.5mm jack plug of the trigger to the submini plug of the flash. piece of cake. Just wish I could get my sunpak 344d running again so I can test with multi flashes.
One thing I didn't even think about when running remote flashes is the shutter speed vs aperture. It's probably common sense but I had no idea that i had to run slower shutter speeds on higher apertures in order to not get either a black image or half an image (like, bright up the top, black down the bottom), eg. f8.0 with 1/80th shutter speed, as opposed to f2.8 with 1/200th shutter speed... ok I'm totally new to this, but that's a tidbit i wish someone had told me about earlier 
Matt
40D, 10D, Canon f/1.8 50mm, Sigma f/2.8 24-60mm, Sigma 70-300mm f/4-5.6 APO Macro Super, Focal 135mm f/2.8, Vivitar 200mm f/3.5, Sunpak 344, Sunpak 333, Photoshop CS3 and Lightroom 2.3
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