The pack/head combo I've heard the most negative about in terms of safety is Novatron - well, them and old Normans. But again, it's just a matter of taking reasonable safety precautions. Don't connect/disconnect heads while the pack is powered up. If you need to change the configuration after powering up, power down and then quick give a test pop to make sure the capacitors are discharged before adding/removing/switching heads. The few extra seconds added to the process are well worth your health and life. Not that a small power pack can't kill you too, but it is especially important when working with those high-output packs (800 w/s and above). If you've got a fussy heart to begin with, a hotshoe flash can kill you, frankly. I once was removing the film from a disposable camera at the lab where I worked after college, and the capacitor was still charged. I pried the battery out and in the process completed the circuit one last time - my hand tingled for a day! Treat ALL electrical appliances with care.