You need a scooter that has enough torque to pull your extra gear. In addition, you need one that can tow you and your partner, should one scooter fail, to your safety zone. Forgive me, I do know the two last models you mentioned. If they have similar specifications as those mentioned below, they should work for you adequately. Not all DPVs have identical ride characteristic and features. The handle, the leash mounting points, accessory attachment should play a role in your decision making process. However, you shouldn't sacrifice accessories for torque and range.
Submerge Viper/Magnus
Suex Xjoy37
Logic Dive Gear Genesis
Bonex RS
DiveXTra Piranha
A DPV is one the most expensive purchase, a diver will make. Buy a DPV for the type of diving you will perform and buy the best your funds allow. If you can't afford one, just save until you can afford a unit with the required specs. Don't buy one with inferior specs. You'll have to sell it and take a hit on the resale value.
O.