Even Mares says the Power Plana's are negative in water.
Power Plana are indeed negative. They are best when you dive dry. Been using them for of couple of years now. Heavy indeed (1,1 kg / 2,2 pounds each), negative, very large feet pocket (ideal with rock boots) and very stiff, but very enjoyable with my dry suit. Tried them in the pool once, for fun, just with swimming trunks on... I dropped to the bottom while swimming...