I am planning to take a DPV class soon and have been looking at your DPVs. The price difference between the 600 and 1200 is only $1K and I was wondering what would be the reason to get a 600 over a 1200 beside being able to transport the batteries on an airplane. I would hate to buy a 600 and realize quickly that a 1200 make more sense. Also, if one has a 1200, couldn't it be converted to a 600 by buying a new nose and battery pack (guess it applies the other away around as well). Thanks.
If you travel to warmer climates and want to take a scooter, the 600 is the only option on the market that gives you realistic run time and decent power. We take our scooters to the Caribbean and do dives that the locals would not even think of doing, because we can get out and back in strong currents and underneath rough surface conditions that the boats won't go out in.
For shore diving, the 600 is easier to manage in the larger breaking waves that are the norm in Monterey and other west coast location. If you are on a dive boat or at a park with 115VAC power, it is very easy to recharge the scooter between dives, since you don't need to open the scooter to recharge. If you dive it for an hour and then recharge for an hour during your surface interval, the batteries will be back up between 80-90% (assuming you didn't hotrod it around your whole dive) and you can do that all day long if you track the charge on the batteries. A few of the places I cave dive in Florida have power outlets at the park and we'll do a 90 minute dive and then charge them for a couple hours before doing the next dive and then maybe do a third dive later, after another recharge. Most folks can get a couple one hour dive on a 600 without recharging and still have plenty of reserve. I know some people that do 3 one hour dives on a charge, with no problem.
The 1200 and 1500 are for 3-5 hour long dives or when you need to do a lot of high speed travel or don't have access to power for recharging in between dives. We have a 1500 owner that is doing exploration in a cave system in Florida that is between 150 and 300ft deep. He has to scooter about a mile to the back of the cave with 8 tanks and a spare scooter in tow, before he really starts the dive, and he does it all at full speed, to minimize his time at depth and the resulting deco hit.
For most folks, the 600 is plenty and has better range than other brands of scooters that are 15-20lbs heavier with larger batteries, since it is more power efficient.
