The advantage of the 7002 over the 3300 is the SUPPLY mode of the 7002.
Smart chargers like the Ctek (and others) will not even attempt to charge a dead or severely discharged battery. This is because they perform a polarity test first, to make sure the leads are correctly connected. If the battery is only outputting a very low voltage, the smart charger does not detect that it is connected to a battery. Thus, no charging in a worst case situation. Which is why many people have two chargers, a smart one and a dumb one (for dead batteries).
The 7002 has a SUPPLY mode which makes the 7002 act like a dumb charger. In SUPPLY mode it just outputs voltage, and will charge a dead battery, if the battery can accept a charge. Once you get the battery charged up enough, you switch the 7002 to RECOND mode to try and recondition the battery back to a reliable condition.
This SUPPLY mode means you don't need to keep a dumb charger around for worst-case situations.
Plus the 7002 charges a little faster than a 3300.