Not so much for Marc, but the reason for having a trigger and not simply doing continuous bulb exposures is that it allows you to shoot lightning in quite bright conditions.
you can only do the bulb approach at night, but with the lightning trigger, you can set say a 1/4 sec exposure, f8, ISO100 and catch lightning during the day (if conditions aren't too bright). trying to do 1/4 sec exposures continously without the trigger soon fills up your memory card!
i've been using one in a few storms here and getting a bit more used to it. this is not the unit i have but has good info:
http://www.lightningtrigger.com/Tips...hotographytips
Phil