DCT = Dual Coil Tank = DCtank
DCT's use cartomizers.
ProTank's use atomizer heads.
The only negative between the two in my opinion is that the ProTank only holds approx 2.5-3ml of liquid. Which may or may not get you through an entire day without refilling.
You can't go wrong with either choice and personally I would buy both. This way you can decide which provides the best
vaping experience for you. Everyone has there own system that works best for their particular needs
It has taken me over two dozen different tanks from various manufacturers to narrow down the ones I use everyday! ;-)